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Evidence that antibiotic administration is effective in the treatment of a subset of patients with intra-amniotic infection/inflammation presenting with cervical insufficiency

  • Kyung Joon Oh
    Affiliations
    Department of Obstetrics and Gynecology, Seoul National University College of Medicine, Seoul, Republic of Korea

    Department of Obstetrics and Gynecology, Seoul National University Bundang Hospital, Seongnam-si, Republic of Korea
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  • Roberto Romero
    Affiliations
    Perinatology Research Branch, NICHD/NIH/DHHS, Bethesda, MD, and Detroit, MI

    Department of Obstetrics and Gynecology, University of Michigan, Ann Arbor, MI

    Department of Epidemiology and Biostatistics, Michigan State University, East Lansing, MI

    Center for Molecular Medicine and Genetics, Wayne State University, Detroit, MI
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  • Jee Yoon Park
    Affiliations
    Department of Obstetrics and Gynecology, Seoul National University College of Medicine, Seoul, Republic of Korea

    Department of Obstetrics and Gynecology, Seoul National University Bundang Hospital, Seongnam-si, Republic of Korea
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  • JoonHo Lee
    Affiliations
    Department of Obstetrics and Gynecology, Institute of Women's Life Medical Science, Yonsei University College of Medicine, Yonsei University Health System, Seoul, Republic of Korea
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  • Agustin Conde-Agudelo
    Affiliations
    Perinatology Research Branch, NICHD/NIH/DHHS, Bethesda, MD, and Detroit, MI

    Department of Obstetrics and Gynecology, Wayne State University School of Medicine, Detroit, MI
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  • Joon-Seok Hong
    Affiliations
    Department of Obstetrics and Gynecology, Seoul National University College of Medicine, Seoul, Republic of Korea

    Department of Obstetrics and Gynecology, Seoul National University Bundang Hospital, Seongnam-si, Republic of Korea
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  • Bo Hyun Yoon
    Correspondence
    Corresponding author: Bo Hyun Yoon, MD, PhD.
    Affiliations
    Department of Obstetrics and Gynecology, Seoul National University College of Medicine, Seoul, Republic of Korea
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Published:March 27, 2019DOI:https://doi.org/10.1016/j.ajog.2019.03.017

      Background

      Cervical insufficiency is a risk factor for spontaneous midtrimester abortion or early preterm birth. Intra-amniotic infection has been reported in 8-52% of such patients and intra-amniotic inflammation in 81%. Some professional organizations have recommended perioperative antibiotic treatment when emergency cervical cerclage is performed. The use of prophylactic antibiotics is predicated largely on the basis that they reduce the rate of complications during the course of vaginal surgery. However, it is possible that antibiotic administration can also eradicate intra-amniotic infection/inflammation and improve pregnancy outcome.

      Objective

      To describe the outcome of antibiotic treatment in patients with cervical insufficiency and intra-amniotic infection/inflammation.

      Study Design

      The study population consisted of 22 women who met the following criteria: (1) singleton pregnancy; (2) painless cervical dilatation of >1 cm between 16.0 and 27.9 weeks of gestation; (3) intact membranes and absence of uterine contractions; (4) transabdominal amniocentesis performed for the evaluation of the microbiologic and inflammatory status of the amniotic cavity; (5) presence of intra-amniotic infection/inflammation; and (6) antibiotic treatment (regimen consisted of ceftriaxone, clarithromycin, and metronidazole). Amniotic fluid was cultured for aerobic and anaerobic bacteria and genital mycoplasmas, and polymerase chain reaction for Ureaplasma spp. was performed. Intra-amniotic infection was defined as a positive amniotic fluid culture for microorganisms or a positive polymerase chain reaction for Ureaplasma spp., and intra-amniotic inflammation was suspected when there was an elevated amniotic fluid white blood cell count (≥19 cells/mm3) or a positive rapid test for metalloproteinase-8 (sensitivity 10 ng/mL). For the purpose of this study, the “gold standard” for diagnosis of intra-amniotic inflammation was an elevated interleukin-6 concentration (>2.6 ng/mL) using an enzyme-linked immunosorbent assay. The results of amniotic fluid interleukin-6 were not available to managing clinicians. Follow-up amniocentesis was routinely offered to monitor the microbiologic and inflammatory status of the amniotic cavity and fetal lung maturity. Treatment success was defined as resolution of intra-amniotic infection/inflammation or delivery ≥34 weeks of gestation.

      Results

      Of 22 patients with cervical insufficiency and intra-amniotic infection/inflammation, 3 (14%) had microorganisms in the amniotic fluid. Of the 22 patients, 6 (27%) delivered within 1 week of amniocentesis and the remaining 16 (73%) delivered more than 1 week after the diagnostic procedure. Among these, 12 had a repeat amniocentesis to assess the microbial and inflammatory status of the amniotic cavity; in 75% (9/12), there was objective evidence of resolution of intra-amniotic inflammation or intra-amniotic infection demonstrated by analysis of amniotic fluid at the time of the repeat amniocentesis. Of the 4 patients who did not have a follow-up amniocentesis, all delivered ≥34 weeks, 2 of them at term; thus, treatment success occurred in 59% (13/22) of cases.

      Conclusion

      In patients with cervical insufficiency and intra-amniotic infection/inflammation, administration of antibiotics (ceftriaxone, clarithromycin, and metronidazole) was followed by resolution of the intra-amniotic inflammatory process or intra-amniotic infection in 75% of patients and was associated with treatment success in about 60% of cases.

      Key words

      Related editorial, page 83.
      The term “cervical insufficiency” refers to a condition in which patients present with a dilated cervix in the midtrimester of pregnancy, protruding membranes in the absence of uterine contractions, or vaginal bleeding.
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      Why was this study conducted?

      • This study explored whether intra-amniotic infection/inflammation in patients with cervical insufficiency can be treated with antibiotics.

      Key findings

      • Seventy-five percent of patients with intra-amniotic infection/inflammation had objective evidence of resolution of the intra-amniotic infectious/inflammatory process after treatment with antibiotics.

      What does this add to what is known?

      • The conventional view is that cervical insufficiency complicated by intra-amniotic infection/inflammation leads to inevitable delivery. Herein we present the first objective evidence that intra-amniotic infection/inflammation can be eradicated with antibiotic treatment, as proven by serial amniotic fluid analysis before and after treatment. This has implications for optimizing patient care.
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      • et al.
      Meconium aspiration syndrome: a role for fetal systemic inflammation.
      • Kesrouani A.
      • Chalhoub E.
      • El Rassy E.
      • et al.
      Prediction of preterm delivery by second trimester inflammatory biomarkers in the amniotic fluid.
      • Kiefer D.G.
      • Peltier M.R.
      • Keeler S.M.
      • et al.
      Efficacy of midtrimester short cervix interventions is conditional on intraamniotic inflammation.
      • Kemp M.W.
      • Molloy T.J.
      • Usuda H.
      • et al.
      Outside-in? Acute fetal systemic inflammation in very preterm chronically catheterized sheep fetuses is not driven by cells in the fetal blood.
      • Oh K.J.
      • Kim S.M.
      • Hong J.S.
      • et al.
      Twenty-four percent of patients with clinical chorioamnionitis in preterm gestations have no evidence of either culture-proven intraamniotic infection or intraamniotic inflammation.
      • Musilova I.
      • Andrys C.
      • Drahosova M.
      • et al.
      Amniotic fluid clusterin in pregnancies complicated by the preterm prelabor rupture of membranes.
      • Gomez-Lopez N.
      • Romero R.
      • Xu Y.
      • et al.
      Are amniotic fluid neutrophils in women with intraamniotic infection and/or inflammation of fetal or maternal origin?.
      • Oh K.J.
      • Park J.Y.
      • Lee J.
      • Hong J.S.
      • Romero R.
      • Yoon B.H.
      The combined exposure to intra-amniotic inflammation and neonatal respiratory distress syndrome increases the risk of intraventricular hemorrhage in preterm neonates.
      Intra-amniotic inflammation has been identified in patients with cervical insufficiency
      • Lee S.E.
      • Romero R.
      • Park C.W.
      • Jun J.K.
      • Yoon B.H.
      The frequency and significance of intraamniotic inflammation in patients with cervical insufficiency.
      • Jung E.Y.
      • Park K.H.
      • Lee S.Y.
      • Ryu A.
      • Oh K.J.
      Non-invasive prediction of intra-amniotic infection and/or inflammation in patients with cervical insufficiency or an asymptomatic short cervix (</=15 mm).
      • Diago Almela V.J.
      • Martinez-Varea A.
      • Perales-Puchalt A.
      • Alonso-Diaz R.
      • Perales A.
      Good prognosis of cerclage in cases of cervical insufficiency when intra-amniotic inflammation/infection is ruled out.
      and is associated with preterm delivery as well as adverse pregnancy and neonatal outcomes.
      • Lee S.E.
      • Romero R.
      • Park C.W.
      • Jun J.K.
      • Yoon B.H.
      The frequency and significance of intraamniotic inflammation in patients with cervical insufficiency.
      • Jung E.Y.
      • Park K.H.
      • Lee S.Y.
      • Ryu A.
      • Oh K.J.
      Non-invasive prediction of intra-amniotic infection and/or inflammation in patients with cervical insufficiency or an asymptomatic short cervix (</=15 mm).
      A subset of patients with intra-amniotic inflammation had no demonstrable microorganisms and, therefore, represented cases of sterile intra-amniotic inflammation, caused by danger signals or alarmins,
      • Kim Y.M.
      • Romero R.
      • Oh S.Y.
      • et al.
      Toll-like receptor 4: a potential link between “danger signals,” the innate immune system, and preeclampsia?.
      • Romero R.
      • Chaiworapongsa T.
      • Alpay Savasan Z.
      • et al.
      Damage-associated molecular patterns (DAMPs) in preterm labor with intact membranes and preterm PROM: a study of the alarmin HMGB1.
      • Romero R.
      • Miranda J.
      • Chaiworapongsa T.
      • et al.
      Prevalence and clinical significance of sterile intra-amniotic inflammation in patients with preterm labor and intact membranes.
      • Romero R.
      • Miranda J.
      • Chaemsaithong P.
      • et al.
      Sterile and microbial-associated intra-amniotic inflammation in preterm prelabor rupture of membranes.
      • Gomez-Lopez N.
      • Romero R.
      • Plazyo O.
      • et al.
      Intra-amniotic administration of HMGB1 induces spontaneous preterm labor and birth.
      • Plazyo O.
      • Romero R.
      • Unkel R.
      • et al.
      HMGB1 induces an inflammatory response in the chorioamniotic membranes that is partially mediated by the inflammasome.
      • Gomez-Lopez N.
      • Romero R.
      • Leng Y.
      • et al.
      Neutrophil extracellular traps in acute chorioamnionitis: a mechanism of host defense.
      which activate the inflammasome. Inflammasome activation can lead to preterm delivery.
      • Oh K.J.
      • Kim S.M.
      • Hong J.S.
      • et al.
      Twenty-four percent of patients with clinical chorioamnionitis in preterm gestations have no evidence of either culture-proven intraamniotic infection or intraamniotic inflammation.
      • Gomez-Lopez N.
      • Romero R.
      • Xu Y.
      • et al.
      A role for the inflammasome in spontaneous preterm labor with acute histologic chorioamnionitis.
      • Gomez-Lopez N.
      • Romero R.
      • Xu Y.
      • et al.
      A role for the inflammasome in spontaneous labor at term with acute histologic chorioamnionitis.
      • Panaitescu B.
      • Romero R.
      • Gomez-Lopez N.
      • et al.
      In vivo evidence of inflammasome activation during spontaneous labor at term.
      • Romero R.
      • Xu Y.
      • Plazyo O.
      • et al.
      A role for the inflammasome in spontaneous labor at term.
      • Gotsch F.
      • Romero R.
      • Chaiworapongsa T.
      • et al.
      Evidence of the involvement of caspase-1 under physiologic and pathologic cellular stress during human pregnancy: a link between the inflammasome and parturition.
      • Strauss 3rd, J.F.
      • Romero R.
      • Gomez-Lopez N.
      • et al.
      Spontaneous preterm birth: advances toward the discovery of genetic predisposition.
      The traditional view has been that intra-amniotic infection in patients with cervical insufficiency cannot be successfully treated, and the same has been so for intra-amniotic inflammation. The objective of this report is to communicate a case series in which women with cervical insufficiency and intra-amniotic infection/inflammation were treated with antimicrobial agents, which resulted in eradication of intra-amniotic infection/inflammation in a subset of patients.

      Materials and Methods

      Study design

      This was a retrospective case series study of patients admitted to Seoul National University Hospital between January 2004 and April 2014 who met the following criteria: (1) singleton gestation; (2) midtrimester painless cervical dilatation (>1 cm) with membranes visible through the cervical os and intact membranes confirmed by sterile speculum examination; (3) gestational age between 16 and 27.9 weeks; (4) absence of uterine contractility based on patient's self-report and a uterine tocodynamometer assessment; (5) transabdominal amniocentesis to evaluate the microbiologic and inflammatory status of the amniotic cavity; (6) presence of intra-amniotic infection/inflammation; and (7) administration of antibiotics (regimen consisted of ceftriaxone, clarithromycin, and metronidazole).
      Intra-amniotic infection was defined as a positive amniotic fluid culture or positive polymerase chain reaction (PCR) assay for Ureaplasma spp., while intra-amniotic inflammation was defined as an elevated amniotic fluid IL-6 concentration (>2.6 ng/mL), as previously reported.
      • Yoon B.H.
      • Romero R.
      • Moon J.B.
      • et al.
      Clinical significance of intra-amniotic inflammation in patients with preterm labor and intact membranes.
      • Gomez-Lopez N.
      • Romero R.
      • Xu Y.
      • et al.
      Are amniotic fluid neutrophils in women with intraamniotic infection and/or inflammation of fetal or maternal origin?.
      • Kim K.W.
      • Romero R.
      • Park H.S.
      • et al.
      A rapid matrix metalloproteinase-8 bedside test for the detection of intraamniotic inflammation in women with preterm premature rupture of membranes.
      • Gervasi M.T.
      • Romero R.
      • Bracalente G.
      • et al.
      Midtrimester amniotic fluid concentrations of interleukin-6 and interferon-gamma-inducible protein-10: evidence for heterogeneity of intra-amniotic inflammation and associations with spontaneous early (<32 weeks) and late (>32 weeks) preterm delivery.
      • Romero R.
      • Kadar N.
      • Miranda J.
      • et al.
      The diagnostic performance of the Mass Restricted (MR) score in the identification of microbial invasion of the amniotic cavity or intra-amniotic inflammation is not superior to amniotic fluid interleukin-6.
      • Combs C.A.
      • Gravett M.
      • Garite T.J.
      • et al.
      Amniotic fluid infection, inflammation, and colonization in preterm labor with intact membranes.
      • Romero R.
      • Miranda J.
      • Chaiworapongsa T.
      • et al.
      Sterile intra-amniotic inflammation in asymptomatic patients with a sonographic short cervix: prevalence and clinical significance.
      • Romero R.
      • Miranda J.
      • Kusanovic J.P.
      • et al.
      Clinical chorioamnionitis at term I: microbiology of the amniotic cavity using cultivation and molecular techniques.
      • Romero R.
      • Grivel J.C.
      • Tarca A.L.
      • et al.
      Evidence of perturbations of the cytokine network in preterm labor.
      • Romero R.
      • Chaemsaithong P.
      • Korzeniewski S.J.
      • et al.
      Clinical chorioamnionitis at term II: the intra-amniotic inflammatory response.
      • Chaemsaithong P.
      • Romero R.
      • Korzeniewski S.J.
      • et al.
      A rapid interleukin-6 bedside test for the identification of intra-amniotic inflammation in preterm labor with intact membranes.
      • Park J.Y.
      • Romero R.
      • Lee J.
      • Chaemsaithong P.
      • Chaiyasit N.
      • Yoon B.H.
      An elevated amniotic fluid prostaglandin F2alpha concentration is associated with intra-amniotic inflammation/infection, and clinical and histologic chorioamnionitis, as well as impending preterm delivery in patients with preterm labor and intact membranes.
      • Chaemsaithong P.
      • Romero R.
      • Docheva N.
      • et al.
      Comparison of rapid MMP-8 and interleukin-6 point-of-care tests to identify intra-amniotic inflammation/infection and impending preterm delivery in patients with preterm labor and intact membranes.
      Cervical dilatation was determined by visual examination at the time of sterile speculum examination.
      • Lee S.E.
      • Romero R.
      • Park C.W.
      • Jun J.K.
      • Yoon B.H.
      The frequency and significance of intraamniotic inflammation in patients with cervical insufficiency.
      • Oh K.J.
      • Lee S.E.
      • Jung H.
      • Kim G.
      • Romero R.
      • Yoon B.H.
      Detection of ureaplasmas by the polymerase chain reaction in the amniotic fluid of patients with cervical insufficiency.
      Previous studies have shown a good correlation between cervical dilatation observed visually and through digital examination.
      • Brown C.L.
      • Ludwiczak M.H.
      • Blanco J.D.
      • Hirsch C.E.
      Cervical dilation: accuracy of visual and digital examinations.
      Every effort was made to avoid digital examination to decrease the risk of ascending intra-amniotic infection.
      Amniocentesis was routinely offered to all patients admitted with the diagnosis of cervical insufficiency to assess the microbiologic status of the amniotic cavity and the presence of intra-amniotic inflammation. This is based on previous studies that reported a 52% prevalence of microbial invasion of the amniotic cavity
      • Romero R.
      • Gonzalez R.
      • Sepulveda W.
      • et al.
      Infection and labor. VIII. Microbial invasion of the amniotic cavity in patients with suspected cervical incompetence: prevalence and clinical significance.
      and an 81% prevalence of intra-amniotic inflammation
      • Lee S.E.
      • Romero R.
      • Park C.W.
      • Jun J.K.
      • Yoon B.H.
      The frequency and significance of intraamniotic inflammation in patients with cervical insufficiency.
      in patients with cervical insufficiency. The prognosis under these circumstances is poor.
      • Romero R.
      • Gonzalez R.
      • Sepulveda W.
      • et al.
      Infection and labor. VIII. Microbial invasion of the amniotic cavity in patients with suspected cervical incompetence: prevalence and clinical significance.
      • Mays J.K.
      • Figueroa R.
      • Shah J.
      • Khakoo H.
      • Kaminsky S.
      • Tejani N.
      Amniocentesis for selection before rescue cerclage.
      • Lee S.E.
      • Romero R.
      • Park C.W.
      • Jun J.K.
      • Yoon B.H.
      The frequency and significance of intraamniotic inflammation in patients with cervical insufficiency.
      • Airoldi J.
      • Pereira L.
      • Cotter A.
      • et al.
      Amniocentesis prior to physical exam-indicated cerclage in women with midtrimester cervical dilation: results from the expectant management compared to Physical Exam-indicated Cerclage international cohort study.
      • Oh K.J.
      • Lee S.E.
      • Jung H.
      • Kim G.
      • Romero R.
      • Yoon B.H.
      Detection of ureaplasmas by the polymerase chain reaction in the amniotic fluid of patients with cervical insufficiency.
      All patients provided written informed consent. The Institutional Review Board of the Seoul National University Hospital approved the collection and use of these samples and clinical information for research purposes. The Seoul National University has a Federal Wide Assurance with the Office for Human Research Protections of the Department of Health and Human Services of the United States.

      Amniotic fluid analysis

      Amniotic fluid was cultured for aerobic and anaerobic bacteria as well as genital mycoplasmas (Ureaplasma spp. and Mycoplasma hominis). Samples were also assayed for Ureaplasma spp. using PCR with specific primers and examined in our clinical microbiology laboratory using methods previously described.
      • Oh K.J.
      • Lee S.E.
      • Jung H.
      • Kim G.
      • Romero R.
      • Yoon B.H.
      Detection of ureaplasmas by the polymerase chain reaction in the amniotic fluid of patients with cervical insufficiency.
      This test has been available in the clinical microbiology laboratory of the hospital since 2007. A PCR assay for Ureaplasma spp. was performed using stored amniotic fluid, which was obtained before 2007. An aliquot of amniotic fluid was examined in a hemocytometer chamber to determine the white blood cell (WBC) count.
      • Yoon B.H.
      • Jun J.K.
      • Park K.H.
      • Syn H.C.
      • Gomez R.
      • Romero R.
      Serum C-reactive protein, white blood cell count, and amniotic fluid white blood cell count in women with preterm premature rupture of membranes.
      Between March 2005 and December 2010, a rapid MMP-8 bedside test (MMP-8 PTD Check Test, SK Pharma Co, Ltd, Kyunggi-do, Republic of Korea), was performed and used in patient management. Details of the MMP-8 rapid test have been previously described.
      • Kim K.W.
      • Romero R.
      • Park H.S.
      • et al.
      A rapid matrix metalloproteinase-8 bedside test for the detection of intraamniotic inflammation in women with preterm premature rupture of membranes.
      • Nien J.K.
      • Yoon B.H.
      • Espinoza J.
      • et al.
      A rapid MMP-8 bedside test for the detection of intra-amniotic inflammation identifies patients at risk for imminent preterm delivery.
      • Park C.W.
      • Lee S.M.
      • Park J.S.
      • Jun J.K.
      • Romero R.
      • Yoon B.H.
      The antenatal identification of funisitis with a rapid MMP-8 bedside test.
      • Kim S.M.
      • Romero R.
      • Lee J.
      • et al.
      About one-half of early spontaneous preterm deliveries can be identified by a rapid matrix metalloproteinase-8 (MMP-8) bedside test at the time of mid-trimester genetic amniocentesis.
      In a subset of patients, MMP-8 concentration in amniotic fluid was measured in our laboratory using a commercially available enzyme-linked immunosorbent assay (Amersham Pharmacia Biotech, Inc, Bucks, UK) and the results were available to clinicians. Intra-amniotic inflammation was suspected when there was an elevated amniotic fluid WBC count (≥19 cells/mm3),
      • Yoon B.H.
      • Romero R.
      • Park J.S.
      • et al.
      Fetal exposure to an intra-amniotic inflammation and the development of cerebral palsy at the age of three years.
      • Park J.S.
      • Romero R.
      • Yoon B.H.
      • et al.
      The relationship between amniotic fluid matrix metalloproteinase-8 and funisitis.
      a positive rapid test for MMP-8,
      • Kim K.W.
      • Romero R.
      • Park H.S.
      • et al.
      A rapid matrix metalloproteinase-8 bedside test for the detection of intraamniotic inflammation in women with preterm premature rupture of membranes.
      • Nien J.K.
      • Yoon B.H.
      • Espinoza J.
      • et al.
      A rapid MMP-8 bedside test for the detection of intra-amniotic inflammation identifies patients at risk for imminent preterm delivery.
      • Park C.W.
      • Lee S.M.
      • Park J.S.
      • Jun J.K.
      • Romero R.
      • Yoon B.H.
      The antenatal identification of funisitis with a rapid MMP-8 bedside test.
      • Kim S.M.
      • Romero R.
      • Lee J.
      • et al.
      About one-half of early spontaneous preterm deliveries can be identified by a rapid matrix metalloproteinase-8 (MMP-8) bedside test at the time of mid-trimester genetic amniocentesis.
      or an MMP-8 concentration >23 ng/mL.
      • Lee S.E.
      • Romero R.
      • Park C.W.
      • Jun J.K.
      • Yoon B.H.
      The frequency and significance of intraamniotic inflammation in patients with cervical insufficiency.
      • Kim S.M.
      • Romero R.
      • Park J.W.
      • Oh K.J.
      • Jun J.K.
      • Yoon B.H.
      The relationship between the intensity of intra-amniotic inflammation and the presence and severity of acute histologic chorioamnionitis in preterm gestation.
      • Park J.S.
      • Romero R.
      • Yoon B.H.
      • et al.
      The relationship between amniotic fluid matrix metalloproteinase-8 and funisitis.
      • Shim S.S.
      • Romero R.
      • Hong J.S.
      • et al.
      Clinical significance of intra-amniotic inflammation in patients with preterm premature rupture of membranes.
      Amniotic fluid not used for clinical diagnostic tests was centrifuged and stored in polypropylene tubes at −70°C. The stored amniotic fluid was analyzed for IL-6, which was measured using a commercially available enzyme-linked immunoassay (R&D Systems, Minneapolis, MN) in 2017 and 2018. The amniotic fluid IL-6 concentrations were measured for research purposes, and the results were not used in clinical decision management. The sensitivity of the assay was 0.7 pg/mL. The intra- and inter-assay coefficients of variation were <10%. For the purpose of this study, the final diagnosis of intra-amniotic inflammation was made when IL-6 concentration was >2.6 ng/mL
      • Yoon B.H.
      • Romero R.
      • Moon J.B.
      • et al.
      Clinical significance of intra-amniotic inflammation in patients with preterm labor and intact membranes.
      .

      Clinical management

      Intra-amniotic inflammation, isolation of microorganisms by amniotic fluid culture, or the detection of Ureaplasma nucleic acids was an indication for antibiotic administration. We used a combination of antimicrobial agents previously described by our group in the management of patients with preterm premature rupture of membranes (PROM),
      • Lee J.
      • Romero R.
      • Kim S.M.
      • et al.
      A new anti-microbial combination prolongs the latency period, reduces acute histologic chorioamnionitis as well as funisitis, and improves neonatal outcomes in preterm PROM.
      • Lee J.
      • Romero R.
      • Kim S.M.
      • et al.
      A new antibiotic regimen treats and prevents intra-amniotic inflammation/infection in patients with preterm PROM.
      including ceftriaxone 1 g (intravenous) every 24 hours, clarithromycin 500 mg (oral) every 12 hours, and metronidazole (intravenous) 500 mg every 8 hours. Metronidazole was administered for a maximum of 4 weeks. A follow-up amniocentesis was offered to monitor the microbiologic and inflammatory status of the amniotic cavity and fetal lung maturity. The use and discontinuation of antibiotics, tocolytics, and progesterone; interval of follow-up amniocentesis; and the placement of a cervical cerclage were left to the discretion of treating clinicians because of the lack of uniformity among attending physicians. Tocolytics used were ritodrine, magnesium sulfate, or atosiban. Nonsteroidal anti-inflammatory agents were not used as tocolytic agents in this study.

      Treatment success

      Treatment success was defined as the resolution of intra-amniotic infection/inflammation (defined as a negative amniotic fluid culture or negative PCR assay for Ureaplasma spp., and as an IL-6 <2.6 ng/mL, respectively) or delivery at or after 34 weeks of gestation.

      Diagnosis of chorioamnionitis and neonatal morbidity

      Acute histologic chorioamnionitis was defined as the presence of acute inflammatory changes in the choriodecidua and amnion, respectively; acute funisitis was diagnosed by the presence of neutrophil infiltration into the umbilical vessel walls or Wharton’s jelly, using previously published criteria.
      • Yoon B.H.
      • Romero R.
      • Kim C.J.
      • et al.
      Amniotic fluid interleukin-6: a sensitive test for antenatal diagnosis of acute inflammatory lesions of preterm placenta and prediction of perinatal morbidity.
      • Kim C.J.
      • Romero R.
      • Chaemsaithong P.
      • Chaiyasit N.
      • Yoon B.H.
      • Kim Y.M.
      Acute chorioamnionitis and funisitis: definition, pathologic features, and clinical significance.
      • Gomez-Lopez N.
      • Romero R.
      • Plazyo O.
      • et al.
      Preterm labor in the absence of acute histologic chorioamnionitis is characterized by cellular senescence of the chorioamniotic membranes.
      • Romero R.
      • Chaemsaithong P.
      • Docheva N.
      • et al.
      Clinical chorioamnionitis at term VI: acute chorioamnionitis and funisitis according to the presence or absence of microorganisms and inflammation in the amniotic cavity.
      Clinical chorioamnionitis was diagnosed in the presence of a maternal temperature of ≥37.8°C and ≥2 of the following criteria: (1) uterine tenderness; (2) malodorous vaginal discharge; (3) maternal leukocytosis (WBC count of >15,000 cells/mm3); (4) maternal tachycardia (>100 beats/min); and (5) fetal tachycardia (>160 beats/min).
      • Gibbs R.S.
      Diagnosis of intra-amniotic infection.
      • Gibbs R.S.
      • Blanco J.D.
      • St Clair P.J.
      • Castaneda Y.S.
      Quantitative bacteriology of amniotic fluid from women with clinical intraamniotic infection at term.
      Significant neonatal morbidity was defined as the presence of any of the following conditions: respiratory distress syndrome, bronchopulmonary dysplasia, intraventricular hemorrhage (grade ≥II), proven congenital neonatal sepsis, and necrotizing enterocolitis. These conditions were diagnosed according to definitions previously described in detail.
      • Yoon B.H.
      • Romero R.
      • Kim C.J.
      • et al.
      Amniotic fluid interleukin-6: a sensitive test for antenatal diagnosis of acute inflammatory lesions of preterm placenta and prediction of perinatal morbidity.
      • Yoon B.H.
      • Romero R.
      • Yang S.H.
      • et al.
      Interleukin-6 concentrations in umbilical cord plasma are elevated in neonates with white matter lesions associated with periventricular leukomalacia.

      Statistical analysis

      Continuous variables were compared between 2 groups using the Mann-Whitney U test. Proportions were compared with a Fisher's exact test. A P value < .05 was considered statistically significant. Analysis was performed by SPSS, version 22 (SPSS Inc, Chicago, IL).

      Results

      Characteristics of the study population

      During the study period, 44 patients with cervical insufficiency had 1 or more amniocentesis. Among these patients, stored amniotic fluid was available for IL-6 determination in 41 patients. Intra-amniotic infection/inflammation was identified in 68% (28/41). Among the 28 patients with intra-amniotic infection/inflammation, the antibiotic regimen (clarithromycin, ceftriaxone, and metronidazole) was administered in 22 cases. The antibiotic regimen was not given to the other 6 patients for the following reasons: 1) intra-amniotic infection/inflammation was not suspected because the patients had a low amniotic fluid WBC count when the MMP-8 rapid test was not available (before March 2005 and after January 2011) (n = 5); however, intra-amniotic inflammation was diagnosed by an elevated IL-6 concentration measured afterward; (2) in 1 patient who had a fever, the managing clinician preferred to use another antibiotic regimen.
      Twenty-two patients with cervical insufficiency had intra-amniotic infection and/or intra-amniotic inflammation and were treated with the antimicrobial agent combination (ceftriaxone, clarithromycin, and metronidazole). Amniotic fluid culture was positive in 2 patients. Microorganisms identified by culture Candida albicans (n = 1) and Streptococcus anginosus (n = 1). Intra-amniotic inflammation was identified in 20 patients with a negative amniotic fluid culture for microorganisms. In one instance, nucleic acids for Ureaplasma spp. were detected using a specific PCR assay.
      The Figure shows the distribution of patients. Among the 22 patients, 6 (27%) delivered within 1 week after amniocentesis and 16 (73%) remained undelivered for at least 1 week after amniocentesis. A repeat amniocentesis to evaluate the therapeutic response to antimicrobial agents was offered to patients and performed in 75% (12/16) of cases; in 75% (9/12) of those cases, there was objective evidence of resolution of intra-amniotic infection or intra-amniotic inflammation. Of the 4 patients who did not have a follow-up amniocentesis, all delivered ≥34 weeks, 2 of them at term (≥37 weeks). Thus, treatment success occurred in 59% (13/22) of patients with cervical insufficiency and intra-amniotic infection/inflammation who received the antibiotic regimen (Figure).
      Figure thumbnail gr1
      FigureFlow diagram of the study population
      Oh et al. Antibiotics in cervical insufficiency. Am J Obstet Gynecol 2019.
      Table 1 compares the clinical characteristics and outcomes of the patients who delivered within 1 week of amniocentesis and those who remained undelivered for at least 1 week after administration of the antibiotic regimen. Patients who delivered within 1 week of amniocentesis had a significantly higher median amniotic fluid IL-6 concentration and a higher rate of history of preterm delivery than those who remained undelivered for at least 1 week after amniocentesis (P = .005 and P = .025, respectively). The median amniotic fluid WBC count and the rate of clinical chorioamnionitis were higher in patients who delivered within 7 days of amniocentesis than in those who were undelivered for at least 1 week after amniocentesis; however, the differences did not reach statistical significance (P > .05 for each, Table 1). Thus, patients with cervical insufficiency who delivered within 1 week of amniocentesis had a more intense intra-amniotic inflammatory response, as determined by the concentrations of a soluble component of the inflammatory response (ie, IL-6). Vaginal progesterone was administered to 2 patients who remained undelivered for at least 1 week.
      Table 1Clinical characteristics and outcomes of patients with cervical insufficiency who received antimicrobial agents
      Delivery before 1 week (N = 6)Delivery after 1 week (N = 16)P value
      Maternal age (years)35 (28–38)32 (24–39).97
      Nulliparity16.7% (1/6)43.8% (7/16).35
      History of preterm delivery66.7% (4/6)12.5% (2/16).025
      GA at amniocentesis (weeks)22.2 (19.7–25.0)23.2 (21.3–27.4).29
      Positive amniotic fluid culture16.7% (1/6)6.3% (1/16).48
      Positive amniotic fluid polymerase chain reaction for Ureaplasma spp.0% (0/4)7.1% (1/14)1.00
      Amniotic fluid white blood cell count (cells/mm3)143 (0–430)7 (0–2556).070
      Amniotic fluid white blood cell count ≥19 cells/mm383.3% (5/6)31.3% (5/16).056
      Amniotic fluid interleukin-6 (ng/mL)47.7 (5.7–49.3)9.4 (2.8–35.4).005
      Amniotic fluid interleukin-6 >2.6 ng/mL100% (6/6)100% (16/16)1.00
      Cervical dilatation >3 cm83.3% (5/6)68.8% (11/16).63
      Cervical cerclage for cervical insufficiency33.3% (2/6)75.0 % (12/16).14
      Use of tocolytics66.7% (4/6)37.5% (6/16).34
      Use of natural vaginal progesterone0% (0/6)12.5% (2/16)1.00
      Use of 17α-hydroxyprogesterone caproate0% (0/6)0% (0/16)1.00
      Antenatal corticosteroids administration33.3% (2/6)43.8% (7/16)1.00
      Gestational age at delivery (weeks)23.0 (20.0–25.7)37.0 (27.0–41.3)<.001
      Preterm labor
      Cases in which preterm delivery before 37 weeks occurred were included.
      33.3% (2/6)18.8% (3/16).59
      Preterm premature rupture of membranes
      Cases in which preterm delivery before 37 weeks occurred were included.
      33.3% (2/6)6.3% (1/16).17
      Clinical chorioamnionitis33.3% (2/6)0% (0/16).065
      Acute histologic chorioamnionitis75% (3/4)57.1% (4/7)1.00
      Funisitis25% (1/4)42.9% (3/7)1.00
      Patients are classified into those who delivered within 1 week of amniocentesis and those who remained undelivered for at least 1 week.
      Data are median (range) or % (n/N).
      Oh et al. Antibiotics in cervical insufficiency. Am J Obstet Gynecol 2019.
      a Cases in which preterm delivery before 37 weeks occurred were included.
      Among the 16 patients who remained undelivered for 1 week after amniocentesis, 12 underwent a follow-up amniocentesis. The median interval between amniocenteses was 8 days (interquartile range, 7-14 days). There were no significant differences in baseline characteristics, results of amniotic fluid analysis at the time of the initial amniocentesis, and median gestational age at delivery between patients who were undelivered for at least 1 week and underwent a follow-up amniocentesis and those who did not undergo another prenatal test.
      Table 2 displays the clinical characteristics according to the results of amniotic fluid analysis obtained at the time of a repeat amniocentesis. Resolution of intra-amniotic infection/inflammation was observed in 75% (9/12) of patients. None of the neonates born to the 9 mothers with resolution of the intra-amniotic inflammatory response had significant complications. The median interval between the initial and follow-up amniocenteses that confirmed resolution of intra-amniotic infection/inflammation was 24 days (interquartile range, 14–30 days). Among the 9 patients, 8 delivered at or beyond 34 weeks of gestation, and 6 delivered at term. The median gestational age at amniocentesis and delivery of patients who delivered at or beyond 34 weeks was 23.4 weeks and 37.8 weeks, respectively. There were no significant differences in the median amniotic fluid WBC count and IL-6 concentration among the 3 groups of patients (P > .1).
      Table 2Antenatal and postnatal characteristics of patients who were treated with antimicrobial agents and underwent follow-up amniocentesis after 1 week from initial amniocentesis
      Resolution of intra-amniotic inflammation
      Confirmed (n = 9)Not confirmed (n = 3)
      Delivery ≥34 weeks (n = 8)Delivery <34 weeks (n = 1)Delivery <34 weeks (n = 3)
      Nulliparity50% (4/8)100% (1/1)33.3% (1/3)
      History of preterm delivery12.5% (1/8)0% (0/1)0% (0/3)
      Initial amniocentesis
       Gestational age at amniocentesis23.4 (21.0–26.7)23.721.4 (21.3–27.4)
       Positive amniotic fluid culture0% (0/8)0% (0/1)33.3% (1/3)
       Positive amniotic fluid polymerase chain reaction for Ureaplasma spp.14.3% (1/7)0% (0/1)0% (0/3)
       Amniotic fluid white blood cell count (cells/mm3)16 (0–282)424 (1–2556)
       Amniotic fluid interleukin-6 (ng/mL)8.9 (2.8–26.2)3.824.8 (10.6–35.4)
      Days from initial amniocentesis to resolution
      The first amniocentesis without evidence of intra-amniotic infection/inflammation
      23 (6–30)30
      Number of amniocenteses3.5 (3–7)34 (3–5)
      Duration of new antibiotic regimen use (days)27 (7–66)3139 (9–43)
      Cervical dilatation > 3cm (%)75% (6/8)100% (1/1)100% (3/3)
      Cervical cerclage for cervical insufficiency50% (4/8)100% (1/1)100% (3/3)
      Gestational age at delivery (weeks)37.8 (34.0–41.3)
      P value < .05.
      29.927.4 (27.0–28.7)
      P value < .05.
      Days from initial amniocentesis to delivery101 (66–131)
      P value < .05.
      4339 (9–43)
      P value < .05.
      Clinical chorioamnionitis0% (0/8)0% (0/1)0% (0/3)
      Acute histologic chorioamnionitis0% (0/3)100% (1/1)100% (3/3)
      Funisitis0% (0/3)100% (1/1)66.7% (2/3)
      Neonatal mortality0% (0/8)0% (0/1)0% (0/3)
      Significant neonatal morbidity0% (0/8)0% (0/1)66.7% (2/3)
      Data are median (range) or % (n/N).
      Oh et al. Antibiotics in cervical insufficiency. Am J Obstet Gynecol 2019.
      a The first amniocentesis without evidence of intra-amniotic infection/inflammation
      b P value < .05.

      Changes in amniotic fluid culture, intra-amniotic inflammatory markers, and pregnancy and neonatal outcomes in patients with a follow-up amniocentesis

      Table 3 shows the characteristics and outcomes of 12 patients who received antibiotics and underwent a follow-up amniocentesis. Nine patients (cases 1–9) had biochemical evidence of successful treatment of intra-amniotic inflammation. Bulging membranes (defined as the prolapse of membranes beyond the external os) were present in 10 of 12 patients (except cases 3 and 6). Three of 4 patients (cases 1, 2, and 4) who did not have cerclage placement had spontaneous reduction of membranes back into the uterine cavity while receiving antibiotic treatment. This was an unexpected observation made during the course of the study.
      Table 3Characteristics and outcomes of 12 patients with administration of antimicrobial agents who underwent follow-up amniocentesis
      Case no.Gestational age (weeks)Cervix dilatation (cm)Bag bulgingCerclage for cervical insufficiencyAnalysis of amniotic fluid (initial amniocentesis)Corticosteroid for fetal lung maturityInterval between initial amniocentesis and resolution (days)
      The first amniocentesis without evidence of intra-amniotic infection/inflammation.
      Acute histologic chorioamnionitis/funisitisOutcome (mother/newborn)
      AmniocentesisDeli-veryCulturePolymerase chain reaction for Ureaplasma spp.Interleukin-6 (ng/mL)White blood cell count (cells/mm3)Matrix metalloproteinase-8 rapid test
      Group A. Resolution confirmed and delivery at or beyond 34 weeks
      124.6343YesNoNegPos4.835PosYes21-/-Rupture of membranes at 25.7 weeks

      Induction of labor at 34 weeks

      Survival without morbidity
      22536.93YesNo
      Prophylactic cerclage was performed at 14.4 weeks of gestation
      NegNeg11.41N/ANo21-/-Survival without morbidity
      323.938.31.5NoNoNegN/A18.114NegNo14N/ASurvival without morbidity
      426.7374YesNoNegNeg2.90PosYes30N/ASurvival without morbidity
      522.641.33YesYesNegNeg10.418N/ANo27N/ASurvival without morbidity
      622.941.11.5NoYesNegNeg2.80N/ANo6N/ASurvival without morbidity
      722.737.34YesYesNegNeg26.2282N/AYes30-/-Survival without morbidity
      821.139.93YesYesNegNegN/A (7.4 on 22.3 week)144N/ANo24N/ASurvival without morbidity
      Group B. Resolution confirmed but delivery before 34 weeks
      923.729.95.5YesYesNegNeg3.84N/AYes30+/+Spontaneous labor

      Survival without morbidity
      Group C. Resolution not confirmed and delivery before 34 weeks
      1021.327.43YesYesNegNeg24.81PosYes-+/+Spontaneous labor

      Respiratory distress syndrome, bronchopulmonary dysplasia, intraventricular hemorrhage
      1121.4273YesYesNegNeg10.624PosYes-+/-Spontaneous labor

      Bronchopulmonary dysplasia
      1227.428.79YesYesCandida albicansNeg35.42556N/AYes-+/+Persistent positive culture for candida and frequent contractions

      Augmentation of labor

      Survival without morbidity
      N/A, not assessed; Neg, negative; Pos, positive.
      Oh et al. Antibiotics in cervical insufficiency. Am J Obstet Gynecol 2019.
      a Prophylactic cerclage was performed at 14.4 weeks of gestation
      b The first amniocentesis without evidence of intra-amniotic infection/inflammation.
      Of 9 patients in whom the resolution of intra-amniotic inflammation was confirmed by IL-6 determinations retrospectively, 7 underwent an additional amniocentesis after resolution. The number of amniocenteses after resolution was 1 for 6 patients and 2 for 1 patient. The procedures were performed due to the occurrence of labor or rupture of membranes (n = 3), a positive result of rapid MMP-8 test at the last amniocentesis (n = 1), acute elevation of maternal serum C-reactive protein and mild fever (n = 1), or reevaluation of intra-amniotic infection/inflammation at the discretion of the clinician caring for the patient (n = 2).
      Intra-amniotic infection was eradicated in case 1: Ureaplasma spp. had been detected by PCR. This patient had an amniotic fluid IL-6 concentration of 4.8 ng/mL, a WBC count of 35 cells/mm3, and a positive rapid test for MMP-8 at initial amniocentesis (24.6 weeks). The antibiotics were administered after the first amniocentesis. One week later (25.6 weeks), membrane rupture occurred but follow-up amniocentesis revealed improvement of inflammatory markers (IL-6 concentration of 0.19 ng/mL, WBC count of 6 cells/mm3, and a weakly positive MMP-8 rapid kit test). The PCR test for Ureaplasma spp. was still positive. The fourth amniocentesis at 27.6 weeks showed no evidence of Ureaplasma spp. by cultivation or specific PCR assay, and all parameters of intra-amniotic inflammation improved (ie, IL-6 concentration of 0.17 ng/mL, WBC count of 6 cells/mm3, and a negative MMP-8 rapid kit test). At 34 weeks of gestation, the patient underwent labor induction secondary to preterm PROM. A neonate weighing 2000 g was delivered and did not develop any complications. There was no evidence of acute histologic chorioamnionitis or funisitis in placental pathologic examination.
      Intra-amniotic infection with Candida albicans was identified in 1 patient (case 12). There was evidence of an intense amniotic fluid inflammatory response (ie, IL-6 concentration of 35.4 ng/mL and WBC count of 2556 cells/mm3), and the amniotic fluid culture was eventually positive for Candida albicans. A repeat amniocentesis showed a very high WBC count (1305 cells/mm3) and the managing physician and patient elected to proceed with labor induction given the concern for congenital candidiasis. The repeat amniotic fluid culture showed that Candida albicans was still present. After completion of corticosteroid administration for fetal lung maturation, the patient delivered at 28.7 weeks of gestation (10 days from initial amniocentesis) by oxytocin administration. The birthweight was 1100 g, and Apgar scores at 1 and 5 minutes were 7 and 8, respectively. The neonate survived without any significant morbidity, and placental examination showed acute histologic chorioamnionitis and funisitis.
      Resolution of intra-amniotic inflammation was noted in 8 patients with a negative amniotic fluid culture and PCR (cases 2-9). Among these, 7 delivered at term (cases 3-8) or near term (case 2, delivered at 36.9 weeks by elective cesarean delivery). One patient (case 9) delivered at 29.9 weeks despite the resolution of intra-amniotic inflammation. The initial amniotic fluid inflammatory markers were as follows: IL-6 concentration, 3.8 ng/mL and WBC count, 4 cells/mm3. After 4 weeks of treatment with the antibiotic regimen, the amniotic fluid IL-6 concentration decreased to 1.0 ng/mL and the amniotic fluid WBC count was 2 cells/mm3. Antibiotics were discontinued, and the patient was discharged from the hospital. Ten days later, the patient was readmitted with spontaneous preterm labor, and the amniotic fluid IL-6 concentration had increased to 2.4 ng/mL. The patient progressed to spontaneous delivery at 29.9 weeks. The neonate weighed 1610 grams and survived without any significant morbidity. Acute histologic chorioamnionitis and funisitis were diagnosed upon placental examination.
      Antibiotic treatment was not successful in 2 patients with intra-amniotic inflammation but without intra-amniotic infection (cases 10 and 11). Of these 2, microbial invasion of the amniotic cavity (by Candida tropicalis after 6 weeks from the initial amniocentesis in case 10, and by Enterococcus faecalis after 8 days from the initial amniocentesis in case 11) was identified in the follow-up amniocentesis. These 2 patients delivered at 27.4 weeks (1220 g) and 27 weeks (1220 g), respectively, because of spontaneous labor. The neonates survived but had respiratory distress syndrome (case 10), bronchopulmonary dysplasia (cases 10 and 11), and intraventricular hemorrhage (case 10).

      Pregnancy and neonatal outcomes in patients who did not have a follow-up amniocentesis

      Table 4 shows the clinical characteristics and outcomes of 4 patients who received antibiotics and remained undelivered for at least 1 week after amniocentesis, but did not have a follow-up amniocentesis. All 4 patients underwent an emergency cervical cerclage, and antibiotics were postoperatively administered for 4-5 days. Follow-up amniocentesis was not performed because there was no evidence of intra-amniotic infection/inflammation at initial amniocentesis (low amniotic fluid WBC count and negative culture; rapid MMP-8 test was not available at this time) in cases 14 and 16, or because of the decision made by the attending physician (cases 13 and 15). All patients in this group delivered after 34 weeks of gestation.
      Table 4Characteristics and outcomes of 4 patients with administration of antimicrobial agents who delivered after 1 week of amniocentesis without follow-up amniocentesis
      Gestational age (weeks)Cervix dilatation (cm)Bag bulgingCerclage for cervical insufficiencyAnalysis of amniotic fluidCorticosteroid for fetal lung maturityAcute histologic chorioamnionitis/funisitisNeonatal outcome
      Case no.AmniocentesisDeliveryCulturePolymerase chain reaction for Ureaplasma spp.Interleukin-6 (ng/mL)White blood cell count (cells/mm3)Matrix metallo proteinase-8 rapid kit
      1321.6393YesYesNegNeg8.31PosNoN/ASurvival without morbidity
      142336.12NoYesNegNeg2.82N/ANoN/ASurvival without morbidity
      1523.439.42YesYesNegN/A3.01PosNoN/ASurvival without morbidity
      1624.635.72YesYesNegNeg16.29N/ANoN/ASurvival without morbidity
      N/A, not assessed; Neg, negative; Pos, positive.
      Oh et al. Antibiotics in cervical insufficiency. Am J Obstet Gynecol 2019.
      Table 5 summarizes the characteristics and outcomes of the 6 patients who delivered within 1 week of amniocentesis and received antibiotics. These patients had a significantly higher amniotic fluid IL-6 concentration than those who remained undelivered for at least 1 week after amniocentesis (P = .005, Table 1). The indication of delivery was clinical chorioamnionitis (cases 21 and 22), progression of spontaneous labor after preterm PROM (case 19) or with intact membranes (case 20), abruptio placentae (case 17), or the patient’s refusal to maintain pregnancy (case 18). Only 1 neonate survived with bronchopulmonary dysplasia (case 17) and the other 5 neonates died shortly after birth.
      Table 5Characteristics and outcomes of 6 patients delivered within 1 week of amniocentesis who received antibiotics
      Gestational age (weeks)Cervix dilatation (cm)Bag bulgingCerclage for cervical insufficiencyAnalysis of amniotic fluidCorticosteroid for fetal lung maturityAcute histologic chorioamnionitis/funisitisOutcome (mother/newborn)
      Case no.AmniocentesisDeliveryCulturePolymerase chain reaction for Ureaplasma spp.Interleukin-6 (ng/mL)White blood cell count (cells/mm3)Matrix metalloproteinase-8 rapid kit
      1724.124.92YesYesNegN/A47.7430PosYes+/-Preterm labor and delivery due to placenta abruptio
      Survival with bronchopulmonary dysplasia
      1823.624.43YesNoNegNeg5.70PosNoN/APatient elected termination of pregnancy at other hospital
      Neonatal death
      1920.721.64YesYesNegN/A26.9123PosNo+/+Progress to spontaneous labor after rupture of membranes
      Neonatal death
      2019.720Full dilatationYesNoNegNeg48.7360N/ANo+/-Spontaneous preterm labor
      Neonatal death
      2119.720.34YesNoStreptococcus anginosusNeg47.781N/ANoN/AClinical chorioamnionitis
      Patient elected termination of pregnancy
      Neonatal death
      222525.73YesNoNegNeg49.3162PosYes-/-Clinical chorioamnionitis after rupture of membranes
      Neonatal death
      N/A, not assessed; Neg, negative; Pos, positive.
      Oh et al. Antibiotics in cervical insufficiency. Am J Obstet Gynecol 2019.

      Comment

      Principal findings of the study

      Principal findings were as follows: (1) eradication of intra-amniotic infection/inflammation was achieved in 75% (9/12) of patients with cervical insufficiency who were treated with antimicrobial agents; and (2) the overall treatment success (defined as resolution of intra-amniotic infection/inflammation or delivery ≥34 weeks) was 59% (13/22). These observations provide strong evidence that antibiotic administration can be effective in treating intra-amniotic infection/inflammation in patients with cervical insufficiency.

      Recognition of cervical insufficiency as a clinical entity

      The initial recognition of cervical insufficiency is attributed to Culpeper, Cole, and Rowland in their 1658 publication “Practice of Physick,”
      and the term “cervical incompetence” was first mentioned in 1865 by Gream.
      • Grant A.
      Cervical cerclage to prolong pregnancy.
      In 1950, Lash and Lash described a condition called “incompetent internal os of the cervix” as a cause of habitual abortion.
      • Lash A.F.
      • Lash S.R.
      Habitual abortion; the incompetent internal os of the cervix.
      Currently, the term “cervical insufficiency” has replaced “cervical incompetence” to avoid the negative connotation of “incompetence.”
      • Romero R.
      • Espinoza J.
      • Erez O.
      • Hassan S.
      The role of cervical cerclage in obstetric practice: can the patient who could benefit from this procedure be identified?.
      The standard treatment for this condition, cervical cerclage, was introduced in 1955 by Shirodkar
      • Shirodkar V.N.
      A new method of operative treatment for habitual abortions in the second trimester of pregnancy.
      and in 1957 by McDonald.
      • McDonald I.A.
      Suture of the cervix for inevitable miscarriage.
      The role of cerclage in obstetrics has remained controversial for more than 60 years.
      • Vintzileos A.M.
      • Visser G.H.
      Interventions for women with mid-trimester short cervix: which ones work?.
      • Guzman E.R.
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      Pregnancy outcomes in women treated with elective versus ultrasound-indicated cervical cerclage.
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      • et al.
      Cerclage for sonographic short cervix in singleton gestations without prior spontaneous preterm birth: systematic review and meta-analysis of randomized controlled trials using individual patient-level data.
      • Roman A.
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      Efficacy of ultrasound-indicated cerclage in twin pregnancies, REPLAY.
      • Jarde A.
      • Lutsiv O.
      • Park C.K.
      • et al.
      Preterm birth prevention in twin pregnancies with progesterone, pessary, or cerclage: a systematic review and meta-analysis.
      • Adams T.M.
      • Rafael T.J.
      • Kunzier N.B.
      • Mishra S.
      • Calixte R.
      • Vintzileos A.M.
      Does cervical cerclage decrease preterm birth in twin pregnancies with a short cervix?.
      • Conde-Agudelo A.
      • Romero R.
      Vaginal progesterone to prevent preterm birth in pregnant women with a sonographic short cervix: clinical and public health implications.
      • Oyelese Y.
      Cerclage in twin pregnancies: we should wait before making definitive recommendations.
      • Sharvit M.
      • Weiss R.
      • Ganor Paz Y.
      • Tzadikevitch Geffen K.
      • Danielli Miller N.
      • Biron-Shental T.
      Vaginal examination vs. cervical length - which is superior in predicting preterm birth?.
      • Sanchez-Ramos L.
      Vaginal progesterone is an alternative to cervical cerclage in women with a short cervix and a history of preterm birth.
      • Conde-Agudelo A.
      • Romero R.
      • Da Fonseca E.
      • et al.
      Vaginal progesterone is as effective as cervical cerclage to prevent preterm birth in women with a singleton gestation, previous spontaneous preterm birth, and a short cervix: updated indirect comparison meta-analysis.
      • Romero R.
      • Conde-Agudelo A.
      • Da Fonseca E.
      • et al.
      Vaginal progesterone for preventing preterm birth and adverse perinatal outcomes in singleton gestations with a short cervix: a meta-analysis of individual patient data.
      • Makrydimas G.
      • Barmpalia Z.
      • Sotiriadis A.
      Cervical cerclage for women with shortening cervix while on progesterone.
      • Romero R.
      • Conde-Agudelo A.
      • Nicolaides K.H.
      There is insufficient evidence to claim that cerclage is the treatment of choice for patients with a cervical length <10 mm.
      • Monsanto S.P.
      • Daher S.
      • Ono E.
      • et al.
      Cervical cerclage placement decreases local levels of proinflammatory cytokines in patients with cervical insufficiency.
      • Oyelese Y.
      • Powel J.
      • Benito C.W.
      Perhaps cerclage is the ideal treatment for the cervix <1 cm.

      Intra-amniotic infection in cervical insufficiency

      Goodlin
      • Goodlin R.C.
      Cervical incompetence, hourglass membranes, and amniocentesis.
      proposed a role for intra-amniotic infection and amniocentesis to study the microbial status of the amniotic cavity and decompression of the uterus by removing amniotic fluid prior to placement of a cerclage. Goodlin reported that 22.2% (2/9) of patients with cervical insufficiency had microorganisms in the amniotic cavity (1 had Escherichia coli and the other had group B Streptococcus).
      • Goodlin R.C.
      Cervical incompetence, hourglass membranes, and amniocentesis.
      He proposed treatment of intra-amniotic infection with the administration of ampicillin into the amniotic cavity at the time of amniocentesis. The patient with group B Streptococcus carried the pregnancy to term, suggesting a therapeutic value for antibiotic administration.
      • Goodlin R.C.
      Cervical incompetence, hourglass membranes, and amniocentesis.
      Subsequent studies have shown that microorganisms are present in the amniotic cavity in 8–52% of patients with cervical insufficiency.
      • Goodlin R.C.
      Cervical incompetence, hourglass membranes, and amniocentesis.
      • Romero R.
      • Gonzalez R.
      • Sepulveda W.
      • et al.
      Infection and labor. VIII. Microbial invasion of the amniotic cavity in patients with suspected cervical incompetence: prevalence and clinical significance.
      • Mays J.K.
      • Figueroa R.
      • Shah J.
      • Khakoo H.
      • Kaminsky S.
      • Tejani N.
      Amniocentesis for selection before rescue cerclage.
      • Lee S.E.
      • Romero R.
      • Park C.W.
      • Jun J.K.
      • Yoon B.H.
      The frequency and significance of intraamniotic inflammation in patients with cervical insufficiency.
      • Bujold E.
      • Morency A.M.
      • Rallu F.
      • et al.
      Bacteriology of amniotic fluid in women with suspected cervical insufficiency.
      • Airoldi J.
      • Pereira L.
      • Cotter A.
      • et al.
      Amniocentesis prior to physical exam-indicated cerclage in women with midtrimester cervical dilation: results from the expectant management compared to Physical Exam-indicated Cerclage international cohort study.
      • Oh K.J.
      • Lee S.E.
      • Jung H.
      • Kim G.
      • Romero R.
      • Yoon B.H.
      Detection of ureaplasmas by the polymerase chain reaction in the amniotic fluid of patients with cervical insufficiency.
      • Lisonkova S.
      • Sabr Y.
      • Joseph K.S.
      Diagnosis of subclinical amniotic fluid infection prior to rescue cerclage using gram stain and glucose tests: an individual patient meta-analysis.
      For example, in a study including 33 patients with cervical insufficiency, 51.5% (17/33) had a positive amniotic fluid culture for microorganisms.
      • Romero R.
      • Gonzalez R.
      • Sepulveda W.
      • et al.
      Infection and labor. VIII. Microbial invasion of the amniotic cavity in patients with suspected cervical incompetence: prevalence and clinical significance.
      Four of these patients had a cervical cerclage because the amniotic fluid Gram stain results were negative. All had complications, which consisted of rupture of membranes, clinical chorioamnionitis, or bleeding. When a cervical cerclage was not placed in patients with intra-amniotic infection, all (13/13) had a preterm delivery. On the other hand, patients without intra-amniotic infection had a favorable outcome, suggesting that the microbial status of the amniotic cavity is a major determinant of pregnancy outcome in patients with cervical insufficiency.

      Intra-amniotic inflammation in cervical insufficiency

      Microbial products (endotoxin or lipopolysaccharide, peptidoglycans, and glucans) and microorganisms can elicit an inflammatory response.
      • Gravett M.G.
      • Hummel D.
      • Eschenbach D.A.
      • Holmes K.K.
      Preterm labor associated with subclinical amniotic fluid infection and with bacterial vaginosis.
      • Fortunato S.J.
      • Menon R.P.
      • Swan K.F.
      • Menon R.
      Inflammatory cytokine (interleukins 1, 6 and 8 and tumor necrosis factor-alpha) release from cultured human fetal membranes in response to endotoxic lipopolysaccharide mirrors amniotic fluid concentrations.
      • Keelan J.A.
      • Sato T.
      • Mitchell M.D.
      Interleukin (IL)-6 and IL-8 production by human amnion: regulation by cytokines, growth factors, glucocorticoids, phorbol esters, and bacterial lipopolysaccharide.
      • Gomez R.
      • Romero R.
      • Ghezzi F.
      • Yoon B.H.
      • Mazor M.
      • Berry S.M.
      The fetal inflammatory response syndrome.
      • Romero R.
      • Gomez R.
      • Chaiworapongsa T.
      • Conoscenti G.
      • Kim J.C.
      • Kim Y.M.
      The role of infection in preterm labour and delivery.
      • Moss T.J.
      • Davey M.G.
      • Harding R.
      • Newnham J.P.
      Effects of intra-amniotic endotoxin on lung structure and function two months after term birth in sheep.
      • Goncalves L.F.
      • Chaiworapongsa T.
      • Romero R.
      Intrauterine infection and prematurity.
      • Grigsby P.L.
      • Hirst J.J.
      • Scheerlinck J.P.
      • Phillips D.J.
      • Jenkin G.
      Fetal responses to maternal and intra-amniotic lipopolysaccharide administration in sheep.
      • Newnham J.P.
      • Kallapur S.G.
      • Kramer B.W.
      • et al.
      Betamethasone effects on chorioamnionitis induced by intra-amniotic endotoxin in sheep.
      • Elovitz M.A.
      • Wang Z.
      • Chien E.K.
      • Rychlik D.F.
      • Phillippe M.
      A new model for inflammation-induced preterm birth: the role of platelet-activating factor and Toll-like receptor-4.
      • Moss T.J.
      • Nitsos I.
      • Ikegami M.
      • Jobe A.H.
      • Newnham J.P.
      Experimental intrauterine Ureaplasma infection in sheep.
      • Romero R.
      • Espinoza J.
      • Goncalves L.F.
      • Kusanovic J.P.
      • Friel L.
      • Hassan S.
      The role of inflammation and infection in preterm birth.
      • Novy M.J.
      • Duffy L.
      • Axthelm M.K.
      • et al.
      Ureaplasma parvum or Mycoplasma hominis as sole pathogens cause chorioamnionitis, preterm delivery, and fetal pneumonia in rhesus macaques.
      • Romero R.
      • Dey S.K.
      • Fisher S.J.
      Preterm labor: one syndrome, many causes.
      • Latino M.A.
      • Botta G.
      • Badino C.
      • et al.
      Association between genital mycoplasmas, acute chorioamnionitis and fetal pneumonia in spontaneous abortions.
      In practice, it is easier and faster to diagnose intra-amniotic inflammation than intra-amniotic infection because an elevated amniotic fluid WBC count or inflammatory molecules (such as IL-6 or MMP-8) can be rapidly detected in clinical practice, whereas the results of amniotic fluid culture or molecular microbiologic techniques will take longer than a bedside test.
      • Kim K.W.
      • Romero R.
      • Park H.S.
      • et al.
      A rapid matrix metalloproteinase-8 bedside test for the detection of intraamniotic inflammation in women with preterm premature rupture of membranes.
      • Chaemsaithong P.
      • Romero R.
      • Korzeniewski S.J.
      • et al.
      A rapid interleukin-6 bedside test for the identification of intra-amniotic inflammation in preterm labor with intact membranes.
      • Park J.Y.
      • Romero R.
      • Lee J.
      • Chaemsaithong P.
      • Chaiyasit N.
      • Yoon B.H.
      An elevated amniotic fluid prostaglandin F2alpha concentration is associated with intra-amniotic inflammation/infection, and clinical and histologic chorioamnionitis, as well as impending preterm delivery in patients with preterm labor and intact membranes.
      • Chaemsaithong P.
      • Romero R.
      • Docheva N.
      • et al.
      Comparison of rapid MMP-8 and interleukin-6 point-of-care tests to identify intra-amniotic inflammation/infection and impending preterm delivery in patients with preterm labor and intact membranes.
      • Nien J.K.
      • Yoon B.H.
      • Espinoza J.
      • et al.
      A rapid MMP-8 bedside test for the detection of intra-amniotic inflammation identifies patients at risk for imminent preterm delivery.
      • Park C.W.
      • Lee S.M.
      • Park J.S.
      • Jun J.K.
      • Romero R.
      • Yoon B.H.
      The antenatal identification of funisitis with a rapid MMP-8 bedside test.
      • Kim S.M.
      • Romero R.
      • Lee J.
      • et al.
      About one-half of early spontaneous preterm deliveries can be identified by a rapid matrix metalloproteinase-8 (MMP-8) bedside test at the time of mid-trimester genetic amniocentesis.
      • Kacerovsky M.
      • Musilova I.
      • Hornychova H.
      • et al.
      Bedside assessment of amniotic fluid interleukin-6 in preterm prelabor rupture of membranes.
      • Chaiyasit N.
      • Romero R.
      • Chaemsaithong P.
      • et al.
      Clinical chorioamnionitis at term VIII: a rapid MMP-8 test for the identification of intra-amniotic inflammation.
      It is now recognized that some cases of intra-amniotic inflammation occur in the absence of demonstrable microorganisms detected with cultivation or molecular methods (“sterile intra-amniotic inflammation”),
      • Yoon B.H.
      • Romero R.
      • Moon J.B.
      • et al.
      Clinical significance of intra-amniotic inflammation in patients with preterm labor and intact membranes.
      • Romero R.
      • Miranda J.
      • Chaiworapongsa T.
      • et al.
      Prevalence and clinical significance of sterile intra-amniotic inflammation in patients with preterm labor and intact membranes.
      • Romero R.
      • Miranda J.
      • Chaemsaithong P.
      • et al.
      Sterile and microbial-associated intra-amniotic inflammation in preterm prelabor rupture of membranes.
      • Gomez-Lopez N.
      • Romero R.
      • Plazyo O.
      • et al.
      Intra-amniotic administration of HMGB1 induces spontaneous preterm labor and birth.
      • Romero R.
      • Miranda J.
      • Chaiworapongsa T.
      • et al.
      Sterile intra-amniotic inflammation in asymptomatic patients with a sonographic short cervix: prevalence and clinical significance.
      • Romero R.
      • Grivel J.C.
      • Tarca A.L.
      • et al.
      Evidence of perturbations of the cytokine network in preterm labor.
      • Shim S.S.
      • Romero R.
      • Hong J.S.
      • et al.
      Clinical significance of intra-amniotic inflammation in patients with preterm premature rupture of membranes.
      and this condition is more common than intra-amniotic infection in patients with a sonographic short cervix.
      • Kiefer D.G.
      • Keeler S.M.
      • Rust O.A.
      • Wayock C.P.
      • Vintzileos A.M.
      • Hanna N.
      Is midtrimester short cervix a sign of intraamniotic inflammation?.
      • Romero R.
      • Miranda J.
      • Chaiworapongsa T.
      • et al.
      Sterile intra-amniotic inflammation in asymptomatic patients with a sonographic short cervix: prevalence and clinical significance.
      The same has been reported in patients with cervical insufficiency with the use of cultivation techniques.
      • Lee S.E.
      • Romero R.
      • Park C.W.
      • Jun J.K.
      • Yoon B.H.
      The frequency and significance of intraamniotic inflammation in patients with cervical insufficiency.
      Specifically, Lee et al
      • Lee S.E.
      • Romero R.
      • Park C.W.
      • Jun J.K.
      • Yoon B.H.
      The frequency and significance of intraamniotic inflammation in patients with cervical insufficiency.
      reported that 81% (42/52) of patients with cervical insufficiency had evidence of intra-amniotic inflammation, defined as an amniotic fluid concentration of MMP-8 >23 ng/mL. Only 4 patients in that study had evidence of intra-amniotic infection using cultivation methods. Therefore, most cases of intra-amniotic inflammation were not attributed to bacteria. The prevalence of intra-amniotic inflammation in other studies has ranged from 22.2% (16/72) to 64.5% (20/31) using different cutoffs of IL-6 concentrations for the definition of intra-amniotic inflammation.
      • Jung E.Y.
      • Park K.H.
      • Lee S.Y.
      • Ryu A.
      • Oh K.J.
      Non-invasive prediction of intra-amniotic infection and/or inflammation in patients with cervical insufficiency or an asymptomatic short cervix (</=15 mm).
      • Diago Almela V.J.
      • Martinez-Varea A.
      • Perales-Puchalt A.
      • Alonso-Diaz R.
      • Perales A.
      Good prognosis of cerclage in cases of cervical insufficiency when intra-amniotic inflammation/infection is ruled out.
      The prognosis of patients with cervical insufficiency and intra-amniotic inflammation is poor, with 50% delivering within 7 days; in 84% of cases, patients had a preterm delivery <34 weeks.
      • Lee S.E.
      • Romero R.
      • Park C.W.
      • Jun J.K.
      • Yoon B.H.
      The frequency and significance of intraamniotic inflammation in patients with cervical insufficiency.
      Importantly, Lee et al reported that there were no differences in the amniocentesis-to-delivery interval or the rate of adverse pregnancy outcome between patients with intra-amniotic inflammation and a negative amniotic fluid culture and patients with proven intra-amniotic infection.
      • Lee S.E.
      • Romero R.
      • Park C.W.
      • Jun J.K.
      • Yoon B.H.
      The frequency and significance of intraamniotic inflammation in patients with cervical insufficiency.
      Collectively, these data suggest that intra-amniotic inflammation is a poor prognostic factor in cervical insufficiency.

      Antimicrobial agents to treat cervical insufficiency

      In this study, clinicians elected to use a combination of ceftriaxone, clarithromycin, and metronidazole based on previous studies of the pharmacokinetics of antibiotics during pregnancy.
      • Witt A.
      • Sommer E.M.
      • Cichna M.
      • et al.
      Placental passage of clarithromycin surpasses other macrolide antibiotics.
      • Kafetzis D.A.
      • Brater D.C.
      • Fanourgakis J.E.
      • Voyatzis J.
      • Georgakopoulos P.
      Ceftriaxone distribution between maternal blood and fetal blood and tissues at parturition and between blood and milk postpartum.
      The rationale has been described in previous reports.
      • Lee J.
      • Romero R.
      • Kim S.M.
      • et al.
      A new anti-microbial combination prolongs the latency period, reduces acute histologic chorioamnionitis as well as funisitis, and improves neonatal outcomes in preterm PROM.
      • Lee J.
      • Romero R.
      • Kim S.M.
      • et al.
      A new antibiotic regimen treats and prevents intra-amniotic inflammation/infection in patients with preterm PROM.
      In brief, erythromycin or azithromycin were frequently inadequate in eradicating intra-amniotic infection with Ureaplasma spp., the most common microorganism identified in the amniotic fluid of patients at risk for preterm delivery, perhaps due to limited transplacental passage, which results in inadequate antimicrobial activity in amniotic fluid (only 3% of erythromycin and 2.6% of azithromycin cross the placenta).
      • Witt A.
      • Sommer E.M.
      • Cichna M.
      • et al.
      Placental passage of clarithromycin surpasses other macrolide antibiotics.
      Clarithromycin, on the other hand, has a much higher rate of transplacental passage, and is effective for the treatment of intra-amniotic infection with Ureaplasma spp.
      • Witt A.
      • Sommer E.M.
      • Cichna M.
      • et al.
      Placental passage of clarithromycin surpasses other macrolide antibiotics.
      Metronidazole was used because of its powerful effect against anaerobic bacteria, which are frequently implicated in intra-amniotic infection.
      • Gauthier D.W.
      • Meyer W.J.
      Comparison of gram stain, leukocyte esterase activity, and amniotic fluid glucose concentration in predicting amniotic fluid culture results in preterm premature rupture of membranes.
      • Cotton D.B.
      • Hill L.M.
      • Strassner H.T.
      • Platt L.D.
      • Ledger W.J.
      Use of amniocentesis in preterm gestation with ruptured membranes.
      • Romero R.
      • Quintero R.
      • Oyarzun E.
      • et al.
      Intraamniotic infection and the onset of labor in preterm premature rupture of the membranes.
      • Garite T.J.
      • Freeman R.K.
      Chorioamnionitis in the preterm gestation.
      These organisms are difficult to identify using cultivation techniques.
      • DiGiulio D.B.
      • Romero R.
      • Kusanovic J.P.
      • et al.
      Prevalence and diversity of microbes in the amniotic fluid, the fetal inflammatory response, and pregnancy outcome in women with preterm pre-labor rupture of membranes.
      Ceftriaxone was included because of its enhanced coverage of aerobic bacteria and high rate of transplacental passage.
      • Kafetzis D.A.
      • Brater D.C.
      • Fanourgakis J.E.
      • Voyatzis J.
      • Georgakopoulos P.
      Ceftriaxone distribution between maternal blood and fetal blood and tissues at parturition and between blood and milk postpartum.
      • Lamb H.M.
      • Ormrod D.
      • Scott L.J.
      • Figgitt D.P.
      Ceftriaxone: an update of its use in the management of community-acquired and nosocomial infections.
      In a previous study, we demonstrated successful eradication of intra-amniotic infection and/or inflammation in at least 33% of patients with preterm PROM after the administration of this antibiotic regimen.
      • Lee J.
      • Romero R.
      • Kim S.M.
      • et al.
      A new antibiotic regimen treats and prevents intra-amniotic inflammation/infection in patients with preterm PROM.

      Can intra-amniotic infection be treated in patients with cervical insufficiency?

      Goodlin
      • Goodlin R.C.
      Cervical incompetence, hourglass membranes, and amniocentesis.
      reported the successful treatment of intra-amniotic infection in 1 case after the administration of a single dose of 1 gram of ampicillin into the amniotic cavity. However, since that report in 1979, there is a paucity of investigation about the treatment of intra-amniotic infection and inflammation. Antibiotics have been successful in eradicating amniotic fluid infection in animal models.
      • Fidel P.
      • Ghezzi F.
      • Romero R.
      • et al.
      The effect of antibiotic therapy on intrauterine infection-induced preterm parturition in rabbits.
      • Grigsby P.L.
      • Novy M.J.
      • Sadowsky D.W.
      • et al.
      Maternal azithromycin therapy for Ureaplasma intraamniotic infection delays preterm delivery and reduces fetal lung injury in a primate model.
      Fidel et al
      • Fidel P.
      • Ghezzi F.
      • Romero R.
      • et al.
      The effect of antibiotic therapy on intrauterine infection-induced preterm parturition in rabbits.
      reported that antibiotic administration within 12 hours of transcervical inoculations of Escherichia coli, but not after 18 hours, increased the duration of pregnancy (by reducing the rate of preterm delivery) and neonatal survival in rabbits. More recently, Grigsby et al
      • Grigsby P.L.
      • Novy M.J.
      • Sadowsky D.W.
      • et al.
      Maternal azithromycin therapy for Ureaplasma intraamniotic infection delays preterm delivery and reduces fetal lung injury in a primate model.
      showed that maternal azithromycin can eradicate Ureaplasma spp. from the amniotic fluid and key fetal organs in a nonhuman primate model. Gravett et al
      • Gravett M.G.
      • Adams K.M.
      • Sadowsky D.W.
      • et al.
      Immunomodulators plus antibiotics delay preterm delivery after experimental intraamniotic infection in a nonhuman primate model.
      reported that the combination of immunomodulators (dexamethasone and indomethacin) and antibiotics was able to eradicate intra-amniotic infection, suppress intra-amniotic and placental inflammation, and prolong gestation in a nonhuman primate model.
      The results reported herein show that antibiotic administration can eradicate intra-amniotic infection, as demonstrated by repeat amniotic fluid analyses of 1 patient who had Ureaplasma spp. detected by PCR at 24.6 weeks of gestation. This patient delivered at 34 weeks and the neonate had no significant morbidity. In contrast, 1 patient was admitted at 27.4 weeks and received antibiotics, and the amniotic fluid culture eventually became positive for Candida albicans. A repeat amniocentesis showed a very high WBC count (1305 cells/mm3) and the managing physician and patient elected to proceed with labor induction given the concern of congenital candidiasis. The repeat amniotic fluid culture showed that Candida albicans was still present. Such observation underscores the importance of identifying the specific microorganism involved and selecting antibiotics that are effective against the pathogen. Previous reports have shown that fluconazole may be effective in cases of intra-amniotic infection with Candida albicans.
      • Bean L.M.
      • Jackson J.R.
      • Dobak W.J.
      • Beiswenger T.R.
      • Thorp J.A.
      Intra-amniotic fluconazole therapy for Candida albicans intra-amniotic infection.

      Antibiotics can eradicate intra-amniotic inflammation in cervical insufficiency

      An observation made during the course of this case series is that antibiotic administration in patients with intra-amniotic inflammation was effective in treating intra-amniotic inflammation, even when microorganisms were not detectable. We have reported similar results in patients with preterm PROM.
      • Lee J.
      • Romero R.
      • Kim S.M.
      • et al.
      A new anti-microbial combination prolongs the latency period, reduces acute histologic chorioamnionitis as well as funisitis, and improves neonatal outcomes in preterm PROM.
      • Lee J.
      • Romero R.
      • Kim S.M.
      • et al.
      A new antibiotic regimen treats and prevents intra-amniotic inflammation/infection in patients with preterm PROM.
      The mechanisms whereby antibiotics can treat intra-amniotic inflammation are not clear. One possibility is that these agents are effective against microorganisms that were not detected using cultivation techniques
      • Romero R.
      • Miranda J.
      • Chaemsaithong P.
      • et al.
      Sterile and microbial-associated intra-amniotic inflammation in preterm prelabor rupture of membranes.
      • Romero R.
      • Miranda J.
      • Chaiworapongsa T.
      • et al.
      Sterile intra-amniotic inflammation in asymptomatic patients with a sonographic short cervix: prevalence and clinical significance.
      • Romero R.
      • Miranda J.
      • Kusanovic J.P.
      • et al.
      Clinical chorioamnionitis at term I: microbiology of the amniotic cavity using cultivation and molecular techniques.
      • DiGiulio D.B.
      • Romero R.
      • Kusanovic J.P.
      • et al.
      Prevalence and diversity of microbes in the amniotic fluid, the fetal inflammatory response, and pregnancy outcome in women with preterm pre-labor rupture of membranes.
      • Jalava J.
      • Mantymaa M.L.
      • Ekblad U.
      • et al.
      Bacterial 16S rDNA polymerase chain reaction in the detection of intra-amniotic infection.
      • Hitti J.
      • Riley D.E.
      • Krohn M.A.
      • et al.
      Broad-spectrum bacterial rDNA polymerase chain reaction assay for detecting amniotic fluid infection among women in premature labor.
      • DiGiulio D.B.
      • Romero R.
      • Amogan H.P.
      • et al.
      Microbial prevalence, diversity and abundance in amniotic fluid during preterm labor: a molecular and culture-based investigation.
      • DiGiulio D.B.
      • Gervasi M.
      • Romero R.
      • et al.
      Microbial invasion of the amniotic cavity in preeclampsia as assessed by cultivation and sequence-based methods.
      • DiGiulio D.B.
      • Gervasi M.T.
      • Romero R.
      • et al.
      Microbial invasion of the amniotic cavity in pregnancies with small-for-gestational-age fetuses.
      • Combs C.A.
      • Garite T.J.
      • Lapidus J.A.
      • et al.
      Detection of microbial invasion of the amniotic cavity by analysis of cervicovaginal proteins in women with preterm labor and intact membranes.
      • Musilova I.
      • Bestvina T.
      • Hudeckova M.
      • et al.
      Vaginal fluid interleukin-6 concentrations as a point-of-care test is of value in women with preterm prelabor rupture of membranes.
      • Rowlands S.
      • Danielewski J.A.
      • Tabrizi S.N.
      • Walker S.P.
      • Garland S.M.
      Microbial invasion of the amniotic cavity in midtrimester pregnancies using molecular microbiology.
      or PCR-specific assays for Ureaplasma spp. Future studies using broad-range PCR assays or cell-free microbial DNA
      • Renko J.
      • Koskela K.A.
      • Lepp P.W.
      • et al.
      Bacterial DNA signatures in carotid atherosclerosis represent both commensals and pathogens of skin origin.
      • Dinakaran V.
      • Rathinavel A.
      • Pushpanathan M.
      • Sivakumar R.
      • Gunasekaran P.
      • Rajendhran J.
      Elevated levels of circulating DNA in cardiovascular disease patients: metagenomic profiling of microbiome in the circulation.
      • Kowarsky M.
      • Camunas-Soler J.
      • Kertesz M.
      • et al.
      Numerous uncharacterized and highly divergent microbes which colonize humans are revealed by circulating cell-free DNA.
      • Wang Z.
      • Tang W.H.
      • Buffa J.A.
      • et al.
      Prognostic value of choline and betaine depends on intestinal microbiota-generated metabolite trimethylamine-N-oxide.
      could help to answer this important question.
      It is also possible that macrolides (ie, clarithromycin) suppress intra-amniotic inflammation caused by danger signals by down-regulating the expression of proinflammatory transcription factors, such as nuclear factor κB and activator protein-1, which can induce the production of proinflammatory cytokines. Such observations have been made in other organ systems.
      • Tamaoki J.
      • Kadota J.
      • Takizawa H.
      Clinical implications of the immunomodulatory effects of macrolides.
      • Shinkai M.
      • Tamaoki J.
      • Kobayashi H.
      • et al.
      Clarithromycin delays progression of bronchial epithelial cells from G1 phase to S phase and delays cell growth via extracellular signal-regulated protein kinase suppression.
      • Simpson J.L.
      • Powell H.
      • Boyle M.J.
      • Scott R.J.
      • Gibson P.G.
      Clarithromycin targets neutrophilic airway inflammation in refractory asthma.
      It is unlikely that antibiotics were effective in reducing decidual infection because careful studies to locate microorganisms in the chorioamniotic membranes and decidua have shown that organisms first invade the amniotic cavity and are only a secondary presence in the decidua. Thus, the initial view that organisms would be present in the decidua and, from there, would invade the amniotic cavity is contradicted by empirical evidence using morphologic and molecular microbiologic techniques.
      • Kim M.J.
      • Romero R.
      • Gervasi M.T.
      • et al.
      Widespread microbial invasion of the chorioamniotic membranes is a consequence and not a cause of intra-amniotic infection.
      A relevant question is the relative contribution of antibiotics and cervical cerclage to the outcomes in this study. There are no data to support that cervical cerclage alone can eradicate intra-amniotic inflammation. A cervical cer-clage was placed in 64% of patients, and it may have had a beneficial effect in improving pregnancy outcome. However, it can be postulated that some patients with intra-amniotic infection/inflammation benefited from the administration of the combination of antimicrobial agents, which eradicated bacteria from the amniotic cavity or down-regulated the inflammatory response.
      For those patients in whom infection or inflammation was successfully treated, a cervical cerclage may have contributed to the prevention of preterm labor or pregnancy loss by closing the cervix and preventing further exposure of the chorioamniotic membranes to microorganisms present in the vagina. Therefore, the improved clinical outcomes observed in this study may have been attributable to the combination of antibiotic administration, with a direct effect on microbial invasion of the amniotic cavity and intra-amniotic inflammation, and cerclage, which prevented reinfection or recurrence of the inflammatory process. Cerclage placement may also have had a protective role by supporting the cervix, as cervical disorders may be a cause of preterm labor and midtrimester pregnancy loss.

      Strengths and limitations

      This is an observational study in which women with intra-amniotic infection/inflammation were treated with antibiotics and monitored with follow-up amniocenteses. It represents an objective demonstration that a case of intra-amniotic infection was successfully treated, and that intra-amniotic inflammation could also be down-regulated and followed by a favorable pregnancy outcome.
      Although Goodlin
      • Goodlin R.C.
      Cervical incompetence, hourglass membranes, and amniocentesis.
      reported the first case of eradication of intra-amniotic infection in cervical insufficiency, the current study reports the successful treatment of intra-amniotic inflammation in the absence of detectable microorganisms. This was possible because of the availability of rapid tests for detection of intra-amniotic inflammation, such as amniotic fluid WBC count and a rapid amniotic fluid test for MMP-8. It is unlikely that the eradication of intra-amniotic inflammation can be attributed to the administration of corticosteroids, because these agents were not administered in 69.2% (9/13) of patients in whom treatment was successful.
      A limitation of this study is that it is not a randomized clinical trial, but rather a case series, and therefore, further studies to confirm these observations are desirable. Another limitation is that we combined patients with intra-amniotic infection and those with intra-amniotic inflammation but without proven intra-amniotic infection. Lee et al
      • Lee S.E.
      • Romero R.
      • Park C.W.
      • Jun J.K.
      • Yoon B.H.
      The frequency and significance of intraamniotic inflammation in patients with cervical insufficiency.
      previously demonstrated that these 2 conditions have similar pregnancy outcomes. Additional research is required to examine whether there is a differential effect of antibiotics in patients with intra-amniotic infection vs those with “sterile” intra-amniotic inflammation. The main claim of this paper is that antimicrobial agents can be useful in eradicating intra-amniotic inflammation and, in some cases, intra-amniotic infection. While our data suggest that the frequency of complications in the neonatal period is lower, other studies will need to examine long-term follow-up.
      This study included patients with cervical insufficiency diagnosed by physical examination, and therefore it does not address the entity of an asymptomatic short cervix diagnosed by ultrasound. We previously demonstrated that microbial invasion of the amniotic cavity in asymptomatic patients with a short cervix can be treated with antibiotics, as demonstrated by repeat amniocentesis in which amniotic fluid cultures became negative, and patients delivered close to term.
      • Hassan S.
      • Romero R.
      • Hendler I.
      • et al.
      A sonographic short cervix as the only clinical manifestation of intra-amniotic infection.
      The choice of antimicrobial agents used in this study, route of administration, and duration of treatment represent the choice of clinicians practicing in a university hospital that has studied intra-amniotic infection/inflammation, the microbiology of infection, and the short- and long-term consequences of these conditions. It is possible that similar success could be achieved with other antibiotic regimens that provide adequate coverage for the most frequent microorganisms found in the amniotic cavity (genital mycoplasmas) and administered in a different manner.
      Medicine is evolving toward the individualized treatment of patients, and we believe that, with the application of modern molecular microbiologic techniques, it may be possible to tailor treatment for a specific patient based on the results of amniotic fluid analysis.

      Conclusion

      Antibiotic administration to women with cervical insufficiency and intra-amniotic infection/inflammation can eradicate these pathologic processes in a subset of patients.

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