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Transabdominal amnioinfusion for preterm premature rupture of membranes: a systematic review and metaanalysis of randomized and observational studies

Published:August 13, 2012DOI:https://doi.org/10.1016/j.ajog.2012.08.003

      Objective

      The purpose of this study was to review systematically the efficacy of transabdominal amnioinfusion (TA) in early preterm premature rupture of membranes (PPROM).

      Study Design

      We conducted a literature search of EMBASE, MEDLINE, and ClinicalTrials.gov databases and identified studies in which TA was used in cases of proven PPROM and oligohydramnios. Risk of bias was assessed for observational studies and randomized controlled trials. Primary outcomes were latency period and perinatal mortality rates.

      Results

      Four observational studies (n = 147) and 3 randomized controlled trials (n = 165) were eligible. Pooled latency period was 14.4 (range, 8.2–20.6) and 11.41 (range −3.4 to 26.2) days longer in the TA group in the observational and the randomized controlled trials, respectively. Perinatal mortality rates were reduced among the treatment groups in both the observational studies (odds ratio, 0.12; 95% confidence interval, 0.02–0.61) and the randomized controlled trials (odds ratio, 0.33; 95% confidence interval, 0.10–1.12).

      Conclusion

      Serial TA for early PPROM may improve early PPROM-associated morbidity and mortality rates. Additional adequately powered randomized control trials are needed.

      Key words

      Preterm premature rupture of membranes (PPROM) complicates approximately 3% of all pregnancies.
      • Mercer B.M.
      Preterm premature rupture of the membranes: current approaches to evaluation and management.
      It is a major cause of neonatal death and morbidity, primarily because of preterm birth. Lack of amniotic fluid may lead to pulmonary hypoplasia, infection, and restrictive joint deformities. Chorioamnionitis negatively affects neonatal prognosis at all gestational ages and warrants prompt delivery. The standard management approach to mid-trimester PPROM includes antibiotic treatment
      • Yudin M.H.
      • van Schalkwyk J.
      • Van Eyk N.
      • et al.
      Antibiotic therapy in preterm premature rupture of the membranes.
      and corticosteroids
      • Harding J.E.
      • Pang J.
      • Knight D.B.
      • Liggins G.C.
      Do antenatal corticosteroids help in the setting of preterm rupture of membranes?.
      to accelerate fetal lung maturity between 24 and 32 weeks of gestation.
      • Miracle X.
      • Di Renzo G.C.
      • Stark A.
      • Fanaroff A.
      • Carbonell-Estrany X.
      • Saling E.
      Guideline for the use of antenatal corticosteroids for fetal maturation.
      Delivery is warranted if there is clinical evidence of chorioamnionitis or fetal distress. Termination of pregnancy may be offered for previable PPROM (<22-23 weeks of gestation) because of the poor prognosis. Despite the relatively high frequency of this condition, controversy regarding the optimal management persists.
      For Editors' Commentary, see Contents
      In recent years, attempts to decrease neonatal mortality and morbidity rates were undertaken with different strategies that included intracervical fibrin application,
      • Sciscione A.C.
      • Manley J.S.
      • Pollock M.
      • et al.
      Intracervical fibrin sealants: a potential treatment for early preterm premature rupture of the membranes.
      amniopatch,
      • Deprest J.
      • Emonds M.P.
      • Richter J.
      • et al.
      Amniopatch for iatrogenic rupture of the fetal membranes.
      fetal endoscopic tracheal occlusion,
      • Kohl T.
      • Geipel A.
      • Tchatcheva K.
      • et al.
      Life-saving effects of fetal tracheal occlusion on pulmonary hypoplasia from preterm premature rupture of membranes.
      • Kohl T.
      • Muller A.
      • Franz A.
      • et al.
      Temporary fetoscopic tracheal balloon occlusion enhanced by hyperoncotic lung distension: is there a role in the treatment of fetal pulmonary hypoplasia from early preterm premature rupture of membranes?.
      antioxidant treatment,
      • Borna S.
      • Borna H.
      • Daneshbodie B.
      Vitamins C and E in the latency period in women with preterm premature rupture of membranes.
      gelatin sponge,
      • O'Brien J.M.
      • Milligan D.A.
      • Barton J.R.
      Gelatin sponge embolization a method for the management of iatrogenic preterm premature rupture of the membranes.
      and progesterone treatment.
      • Briery C.M.
      • Veillon E.W.
      • Klauser C.K.
      • et al.
      Women with preterm premature rupture of the membranes do not benefit from weekly progesterone.
      None of these strategies have proved to be consistently effective, reproducible, or applicable for most centers.
      Amnioinfusion or instillation of physiologic solution into the amniotic cavity was attempted initially to reduce intrapartum variable decelerations.
      • Nageotte M.P.
      • Freeman R.K.
      • Garite T.J.
      • Dorchester W.
      Prophylactic intrapartum amnioinfusion in patients with preterm premature rupture of membranes.
      Later, it was suggested as a treatment modality to prolong the latency period and prevent the oligohydramnios-related sequelae in cases of early PPROM.
      • Szabo I.
      • Szilagyi A.
      • Gacs E.
      • Szekely J.
      Amnioinfusion for management of preterm prelabour rupture of membranes.
      • Fisk N.M.
      • Ronderos-Dumit D.
      • Soliani A.
      • Nicolini U.
      • Vaughan J.
      • Rodeck C.H.
      Diagnostic and therapeutic transabdominal amnioinfusion in oligohydramnios.
      Both transcervical
      • Ogita S.
      • Imanaka M.
      • Matsumoto M.
      • Oka T.
      • Sugawa T.
      Transcervical amnioinfusion of antibiotics: a basic study for managing premature rupture of membranes.
      • Sadovsky Y.
      • Amon E.
      • Bade M.E.
      • Petrie R.H.
      Prophylactic amnioinfusion during labor complicated by meconium: a preliminary report.
      and transabdominal
      • Fisk N.M.
      • Ronderos-Dumit D.
      • Soliani A.
      • Nicolini U.
      • Vaughan J.
      • Rodeck C.H.
      Diagnostic and therapeutic transabdominal amnioinfusion in oligohydramnios.
      routes have been attempted. One of the hypothetic disadvantages of the transcervical route is the nonsterile environment through which the infusion catheter passes, therefore increasing the risk of the introduction of infectious organisms from the vaginal flora into the amniotic sac. Transabdominal amnioinfusion (TA) theoretically surmounts this pitfall. Several articles have described serial TA as a plausible treatment modality to prolong the latency period between rupture of membranes and birth.
      • De Santis M.
      • Scavo M.
      • Noia G.
      • et al.
      Transabdominal amnioinfusion treatment of severe oligohydramnios in preterm premature rupture of membranes at less than 26 gestational weeks.
      Recently, a Cochrane review assessed the efficacy of TA for PPROM with the use of data from 2 randomized trials and concluded that the small number of subjects in those studies precluded a definitive answer in regards to the efficacy of the intervention.
      • Hofmeyr G.J.
      • Essilfie-Appiah G.
      • Lawrie T.A.
      Amnioinfusion for preterm premature rupture of membranes.
      However, additional data are available from observational studies of TA that can shed further light on this topic.
      Our objective was to review systematically and metaanalyze studies that have assessed efficacy and safety of TA in women with PPROM. This systematic review provides results of separate qualitative and quantitative analyses of randomized controlled trials (RCTs) and observational studies.

      Methods

      Search strategy

      We performed a comprehensive literature search, assisted by an experienced librarian, using the MEDLINE from 1950 to December 2011 and EMBASE from 1980 to December 2011. We also searched the ClinicalTrials.gov database for studies that finished recruitment. We used the terms fetal membranes, premature rupture, rupture, membrane*, pregnancy, amnioinfus*, premature fetus membrane rupture, and amnioinfusion. There were no language or geographic restrictions. Bibliography of identified articles was used to screen for additional related articles.

      Study selection

      We included both comparative observational and RCTs in which TA and conventional treatment were compared with conventional treatment alone. Case reports, case series, and abstract publications were excluded. Studies that included patients with a confirmed diagnosis of PPROM-associated oligohydramnios were included. Studies that included oligohydramnios from other causes (eg, intrauterine growth restriction, renal anomalies) were excluded. Two reviewers (S.P. and H.A.) independently evaluated studies for inclusion; disagreements were resolved through consensus among the authors.

      Outcome measures

      The primary outcomes of interest were latency period (interval from PPROM to birth) and perinatal death. Secondary outcomes of interest were pulmonary hypoplasia, neonatal death, gestational age at birth, birthweight, chorioamnionitis, early onset (<72 hours from delivery) neonatal sepsis, bronchopulmonary dysplasia, and cesarean delivery. Two investigators (S.P. and H.A.) independently abstracted the relevant data from selected articles.

      Assessment of risk of bias

      Risk of bias in observational studies was assessed with the Newcastle-Ottawa scale
      • Wells G.A.
      • Shea B.
      • O'Connell D.
      • Peterson J.
      • Welch V.
      • Losos M.
      • Tugwell P.
      The Newcastle-Ottawa Scale (NOS) for assessing the quality of nonrandomised studies in meta-analyses.
      and in RCTs with the Cochrane collaboration's tool.
      For observational studies, the domains of assessment included selection, comparability, and outcome assessment biases. For RCTs, the domains included selection, performance, detection, attrition, reporting, and other biases. Two investigators (S.P. and H.A.) independently assessed risk of bias; discrepancies were resolved through discussion and involvement of third author.

      Data extraction

      Data were extracted in duplicate from published reports by 2 authors who used a standardized data collection form. A third reviewer was consulted in case of disagreement between the 2 data extractors; discrepancy was resolved by consensus. We did not contact authors for missing information. For continuous outcomes, means and standard deviations were obtained from studies. When they were not reported, they were calculated from range, median, and sample size according to the method described by Hozo et al.
      • Hozo S.P.
      • Djulbegovic B.
      • Hozo I.
      Estimating the mean and variance from the median, range, and the size of a sample.
      For categoric outcomes, event rates were obtained.

      Statistical analysis

      Statistical analyses were performed with the Review Manager (RevMan) software (version 5.1.4; The Nordic Cochrane Centre, København, Denmark). Metaanalyses were performed separately for cohort studies and the RCTs. Where data were sufficiently homogenous, metaanalysis was conducted with the use of a random effects model, with weighting of studies according to the DerSimonian-Laird method. Random-effect model was used to account for between and within study heterogeneity. Cochran's Q test was used to test for heterogeneity between studies at the .10 level of significance. The I-squared statistic was used to quantify the degree of heterogeneity.

      Report

      Results of the metaanalysis of RCTs and the observational studies were reported according to the Preferred Reporting Items for Systematic Reviews and Metaanalyses statement
      • Moher D.
      • Liberati A.
      • Tetzlaff J.
      • Altman D.G.
      Preferred reporting items for systematic reviews and meta-analyses: the PRISMA statement.
      and Metaanalysis of the Observational Studies in Epidemiology guidelines,
      • Stroup D.F.
      • Berlin J.A.
      • Morton S.C.
      • et al.
      Meta-analysis of observational studies in epidemiology: a proposal for reporting: Meta-analysis of Observational Studies in Epidemiology (MOOSE) group.
      respectively.

      Results

      Our initial search yielded 141 citations. After review of titles and abstracts, 126 citations were excluded (Figure 1). After full text review of the remaining 15 articles, 8 articles were excluded (3 because inclusion criteria were not fulfilled
      • Szabo I.
      • Szilagyi A.
      • Gacs E.
      • Szekely J.
      Amnioinfusion for management of preterm prelabour rupture of membranes.
      • Fisk N.M.
      • Ronderos-Dumit D.
      • Soliani A.
      • Nicolini U.
      • Vaughan J.
      • Rodeck C.H.
      Diagnostic and therapeutic transabdominal amnioinfusion in oligohydramnios.
      • Chhabra S.
      • Dargan R.
      • Nasare M.
      Antepartum transabdominal amnioinfusion.
      ; 4 because of it was not clear whether reported patients in these studies were included in other studies,
      • Locatelli A.
      • Ghidini A.
      • Verderio M.
      • et al.
      Predictors of perinatal survival in a cohort of pregnancies with severe oligohydramnios due to premature rupture of membranes at <26 weeks managed with serial amnioinfusions.
      • Locatelli A.
      • Vergani P.
      • Di Pirro G.
      • Doria V.
      • Biffi A.
      • Ghidini A.
      Role of amnioinfusion in the management of premature rupture of the membranes at <26 weeks' gestation.
      • Vergani P.
      • Locatelli A.
      • Verderio M.
      • Assi F.
      Premature rupture of the membranes at <26 weeks' gestation: role of amnioinfusion in the management of oligohydramnios.
      • De Carolis M.P.
      • Romagnoli C.
      • De Santis M.
      • Piersigilli F.
      • Vento G.
      • Caruso A.
      Is there significant improvement in neonatal outcome after treating pPROM mothers with amnio-infusion?.
      and 1 because the intervention group and control group were unmatched
      • Turhan N.O.
      • Atacan N.
      Antepartum prophylactic transabdominal amnioinfusion in preterm pregnancies complicated by oligohydramnios.
      ). The remaining 7 studies met inclusion criteria and were included in this review.
      • De Santis M.
      • Scavo M.
      • Noia G.
      • et al.
      Transabdominal amnioinfusion treatment of severe oligohydramnios in preterm premature rupture of membranes at less than 26 gestational weeks.
      • Garzetti G.G.
      • Ciavattini A.
      • De Cristofaro F.
      • La Marca N.
      • Arduini D.
      Prophylactic transabdominal amnioinfusion in oligohydramnios for preterm premature rupture of membranes: increase of amniotic fluid index during latency period.
      • Gramellini D.
      • Fieni S.
      • Kaihura C.
      • Faiola S.
      • Vadora E.
      Transabdominal antepartum amnioinfusion.
      • Ogunyemi D.
      • Thompson W.
      A case controlled study of serial transabdominal amnioinfusions in the management of second trimester oligohydramnios due to premature rupture of membranes.
      • Vergani P.
      • Locatelli A.
      • Strobelt N.
      • et al.
      Amnioinfusion for prevention of pulmonary hypoplasia in second-trimester rupture of membranes.
      • Singla A.
      • Yadav P.
      • Vaid N.B.
      • Suneja A.
      • Faridi M.M.
      Transabdominal amnioinfusion in preterm premature rupture of membranes.
      • Tranquilli A.L.
      • Giannubilo S.R.
      • Bezzeccheri V.
      • Scagnoli C.
      Transabdominal amnioinfusion in preterm premature rupture of membranes: a randomised controlled trial.
      Characteristics of these studies are summarized in Table 1.
      Figure thumbnail gr1
      FIGURE 1Study selection process
      Porat. Transabdominal amnioinfusion for PPROM. Am J Obstet Gynecol 2012.
      TABLE 1Characteristics of included studies
      StudyCharacteristics
      De Santis et al, 2003
      • De Santis M.
      • Scavo M.
      • Noia G.
      • et al.
      Transabdominal amnioinfusion treatment of severe oligohydramnios in preterm premature rupture of membranes at less than 26 gestational weeks.
       Type of studyQuasi-randomized; patients admitted by chance to 1 of 2 divisions of the same department; both divisions offered expectant treatment; only 1 division offered TA
       Participants37 patients in intervention group; 34 patients in control group
        Inclusion criteriaSingleton; PPROM at <26 weeks of gestation; severe and persistent oligohydramnios (AFI <30 mm, lasting ≥7 d)
        Exclusion criteriaClinical chorioamnionitis; active labor; autoimmune or metabolic disease; history of multiple invasive procedures; declining treatment after informed consent; delivery in the interim 7-day waiting period from admission; transfer from other hospitals after a period of treatment
       Diagnosis of PPROMHistory; sterile speculum examination; vaginal pH >5; AFI measurement by ultrasound scanning
       Interventions
        AllHospital bed rest; antibiotic prophylaxis (mezlocillin, 2 g intravenously twice daily for at least 7 days) or targeted treatment based on cultures; tocolytic treatment (isoxsuprine, either intravenously or orally) for contractions; betamethasone after 25 weeks; fetal monitoring by daily heart check or cardiocotography after 26 weeks and modified BPP every 3 days; cesarean delivery performed in the presence of chorioamnionitis, abruptio placentae, and/or fetal distress (abnormal fetal monitoring) or at 30 weeks of gestation
        InterventionWeekly saline amnioinfusion in a sufficient amount to increase AFI to 10 cm starting 7 days at least after PPROM; antibiotics and tocolysis on the day of amnioinfusion
       OutcomesLatency period; gestational age at delivery; cesarean delivery; genitourinary infection, amnionitis/endometritis; neonatal weight; orotracheal intubation; survival; deformities; pulmonary hypoplasia; bronchopulmonary dysplasia; early-onset sepsis; early-onset pneumonitis; abnormal neurologic outcome (includes cerebral palsy, spastic diplegia or tetraplegia, deafness, or blindness)
       NotesAlso included were women who underwent PROM after amniocentesis for prenatal diagnosis: 10 patients (27.0%) in the amnioinfusion group and 8 patients (23.5%) in the control group
      Tranquilli et al 2005
      • Tranquilli A.L.
      • Giannubilo S.R.
      • Bezzeccheri V.
      • Scagnoli C.
      Transabdominal amnioinfusion in preterm premature rupture of membranes: a randomised controlled trial.
       Type of studyRandomized controlled trial
       Participants17 patients in each arm
        Inclusion criteriaSingleton pregnancy with a certain gestational age confirmed by an early second-trimester ultrasonographic examination; gestational age 24-33 weeks; evidence of PPROM within 24 hours of admission; oligohydramnios (amniotic fluid index, <10th percentile); absence of uterine contractions at the time of hospitalization; no evidence of clinical chorioamnionitis at admission; no evidence of placental anomalies or major structural fetal anomalies, and normal cardiotocography at the time of admission
       Diagnosis of PPROMPPROM diagnosed on examination by a sterile speculum when obvious leakage of amniotic fluid from the cervical os was confirmed by a positive fibronectin test
       Interventions
        AllHospital bed rest; antibiotic prophylaxis (sulbactam-ampicillin 3 g, intravenously every 8 hours for 7 days); betamethasone therapy; prophylactic tocolytic (intravenous ritodrine) in the absence of clinical signs of chorioamnionitis or placental abruption; daily fetal heart rate monitoring
        InterventionWeekly serial amnioinfusion if the AFI fell <5th percentile and/or a median pocket of amniotic fluid was <2 cm, with a target AFI of >10th percentile; if repeated AFI was ≤5, amnioinfusion repeated weekly until 27 weeks of gestation; a nonstress test performed daily
       OutcomesLatency period; gestational age at delivery; birthweight; admission to neonatal intensive care unit; pulmonary hypoplasia; abnormal neurologic outcome
      Singla et al, 2010
      • Singla A.
      • Yadav P.
      • Vaid N.B.
      • Suneja A.
      • Faridi M.M.
      Transabdominal amnioinfusion in preterm premature rupture of membranes.
       Type of studyRandomized controlled trial
       Participants30 patients in each arm
        Inclusion criteriaSingleton pregnancy; PPROM between 26 and 33 + 6 week gestations; AFI <5th percentile for gestational age
        Exclusion criteriaWomen with evidence of clinical chorioamnionitis, placental or fetal anomalies; active labor or AFI >5th percentile
       Diagnosis of PPROMSterile speculum examination or nitrazine/litmus paper test; confirmation by ultrasound scanning
       Interventions
        All24 hours of observation after admission before randomization; hospital bed rest; antibiotic prophylaxis (erythromycin: 250-mg tablet 4 times per day for 10 days); betamethasone prophylaxis; daily obstetric examination; weekly BPP, complete blood cell count, and cervical/vaginal cultures
        InterventionAmnioinfusion of warmed saline solution in a sufficient amount to maintain the AFI at >5th percentile for gestational age; weekly AFI measurement and repeated amnioinfusion if the AFI fell <5th percentile; labor induction when there was fetal distress or chorioamnionitis
       OutcomesLatency period; gestational age at delivery; birthweight; intrapartum fetal distress; early neonatal sepsis; rate and causes of neonatal mortality; type and mode of delivery; postpartum sepsis
      Vergani et al, 1997
      • Vergani P.
      • Locatelli A.
      • Strobelt N.
      • et al.
      Amnioinfusion for prevention of pulmonary hypoplasia in second-trimester rupture of membranes.
       Type of studyObservational
       Participants18 patients in intervention group and 16 patients in historic cohort group who did not undergo the procedure
        Inclusion criteriaSingleton pregnancy; PPROM at <25 completed weeks of gestation; no labor; persistent oligohydramnios (maximum pool depth ≤2 cm of cord-free pocket of fluid) at ≥4 days
        Exclusion criteriaAmniotic fluid leakage after second-trimester amniocentesis; clinical chorioamnionitis; presence of uterine contractions ≥4/hour; sonographic diagnosis of structural fetal abnormalities; maternal immunologic diseases; multiple gestations
       Diagnosis of PPROMObservation of vaginal pooling and a positive nitrazine test on sterile speculum examination
       Interventions
        AllHospital bed rest during the first week, then home bed rest until 25 weeks, after which all patients were admitted until delivery; tocolytic treatment (intravenous ritodrine) given at >25 weeks for uterine contractions in the absence of clinical signs of chorioamnionitis or abruption placentae; betamethasone course at least once between 25 and 32 weeks of gestation; 1-week course of prophylactic antibiotic therapy with sulbactam-ampicillin 3 g intravenously every 8 hours and targeted treatment based on cervical and vaginal cultures; sonographic determination of amniotic fluid volume twice a week for outpatients and daily for inpatients; BPP twice a week at >25 weeks of gestation
        Intervention1-2 TA/wk to aim to restore AFI >5 cm; delivery in the presence of clinical chorioamnionitis, fetal distress, abruption placentae, or documented fetal lung maturity on amniocentesis after 28 weeks of gestation
       OutcomesGestational age at delivery; latency period; survival rate; pulmonary hypoplasia; chorioamnionitis; fetal distress; placental abruption; preterm labor; in utero death; umbilical cord prolapse
      Garzetti et al, 1997
      • Garzetti G.G.
      • Ciavattini A.
      • De Cristofaro F.
      • La Marca N.
      • Arduini D.
      Prophylactic transabdominal amnioinfusion in oligohydramnios for preterm premature rupture of membranes: increase of amniotic fluid index during latency period.
       Type of studyObservational
       Participants18 women in each arm; control group recruited from historic data
        Inclusion criteriaSingleton; PPROM between 25 and 32 weeks of gestation; oligohydramnios (AFI, <5th percentile)
        Exclusion criteriaPresence of uncontrolled labor; presence of obstetric complications; maternal immunocompromise; uterine fibroid tumors; lack of written consent
       Diagnosis of PPROMObservation of gross vaginal pooling of amniotic fluid and a positive nitrazine test on speculum examination
       Interventions
        AllHospital bed rest until delivery with minimal activity limited to bathroom necessities; weekly complete blood cell count and semiquantitative C-reactive protein measurement; weekly ultrasound scanning and cardiocotography; daily nonstress test; prophylactic tocolytic treatment (intravenous ritodrine) in the absence of chorioamnionitis or abruption placentae; prophylactic antibiotic treatment (ceftazidime 2 g/d intramuscularly) and targeted therapy based on cultures; delivery in the presence of clinical chorioamnionitis, positive amniotic fluid culture, fetal distress, and documented fetal lung maturity
        InterventionIf AFI <10th percentile for gestational age and deepest pocket of cord-free fluid ≥10 mm, weekly TA of 150-350 mL warmed saline solution; weekly AFI assessment before and after each procedure; biweekly fetal growth assessment
       OutcomesLatency period duration; median amniotic fluid volume and short-term variability; relationship between amniotic fluid volume and fetal short-term variability in the amnioinfusion group
      Ogunyemi and Thompson, 2002
      • Ogunyemi D.
      • Thompson W.
      A case controlled study of serial transabdominal amnioinfusions in the management of second trimester oligohydramnios due to premature rupture of membranes.
       Type of studyObservational
       Participants12 patients in each group
        Inclusion criteriaPPROM at gestational age ≤27 weeks; oligohydramnios with AFI <5 cm; normal fetal anatomic scan; absence of gross infection; stable mother and fetus
        Exclusion criteriaPresence of active labor; clinical chorioamnionitis
       Diagnosis of PPROMObservation of vaginal pooling, a positive nitrazine test or ferning on speculum evaluation
       Interventions
        AllInitial hospital bed rest, followed by outpatient follow-up evaluation for stable patients; corticosteroids after 24 weeks of gestation; magnesium sulfate and terbutaline were used for tocolysis as needed if preterm labor suspected in the absence of clinical chorioamnionitis; prophylactic intravenous antibiotics
        InterventionBefore the procedure, intravenous magnesium sulfate 4 g loading dose followed by 1 g/hr was initiated and discontinued 12 hours after the procedure if preterm labor did not ensue; weekly amnioinfusion of warm 0.9% normal saline solution with ampicillin 1 g/L until 27 weeks of gestation if AFI ≤5
       OutcomesChorioamnionitis; latency period; cesarean delivery rate; gestational age at delivery; birthweight; neonatal sepsis; neonatal death; perinatal death; total death
      Gramellini et al, 2003
      • Gramellini D.
      • Fieni S.
      • Kaihura C.
      • Faiola S.
      • Vadora E.
      Transabdominal antepartum amnioinfusion.
       Type of studyObservational
       Participants24 patients in intervention group and 29 patients in historic control group
        Inclusion criteriaSingleton; <34 weeks gestational age; PPROM; oligohydramnios (AFI, ≤5 cm)
        Exclusion criteriaActive labor; clinical evidence of placental abruption or chorioamnionitis
       Diagnosis of PPROMObservation of persistent vaginal pooling and a positive nitrazine paper test
       Interventions
        AllTocolytic treatment (ritodrine) for >4 uterine contractions/20 min; betamethasone after 24 weeks of gestation; prophylactic antibiotic therapy (erythromycin 2 g/d) given to 90% of patients
        InterventionTA of 0.9% normal saline solution or lactated Ringer's solution according to a volume criterion of 10 mL/gestational week; repeated if AFI measurement >12 hours after the procedure was <5 cm
       OutcomesGestational age at delivery; latency period; birthweight; rate of intrauterine death, vaginal bleeding, cesarean delivery, and postpartum endometritis
       NotesRefers to a group of patients in whom the oligohydramnios was not attributed to PPROM; however, all data cited refer only to patients affected by PPROM
      AFI, amniotic fluid index; BPP, biophysical profile; CBC, complete blood cell count; PPROM, preterm premature rupture of membranes; TA, transabdominal amnioinfusion.
      Porat. Transabdominal amnioinfusion for PPROM. Am J Obstet Gynecol 2012.
      Of the 7 included studies, 2 studies were RCTs (47 patients in each group); 1 study was quasirandomized (34 patients in the control group and 37 in the intervention group), and 4 studies were observational studies (75 patients in the control group and 72 in the intervention group). In the quasirandomized study, patients were admitted by chance to one of 2 departments that differed in their management approach toward PPROM: one department provided standard care; the other department provided standard care in addition to serial amnioinfusion to consented patients. We decided to include the quasirandomized study with the other 2 randomized studies because we believed that the risk of bias in that study was not high. The gestational age at inclusion varied from 16-33 weeks. Information on individual patients was provided only in 1 study
      • Ogunyemi D.
      • Thompson W.
      A case controlled study of serial transabdominal amnioinfusions in the management of second trimester oligohydramnios due to premature rupture of membranes.
      ; therefore, subgroup analysis by gestational age was not possible. Ascertainment of rupture of membranes was performed in all studies by speculum examination to confirm pooling of amniotic fluid in the posterior fornix. In addition, 6 studies used nitrazine, and 1 study used fetal fibronectin as a confirmatory test.
      • Tranquilli A.L.
      • Giannubilo S.R.
      • Bezzeccheri V.
      • Scagnoli C.
      Transabdominal amnioinfusion in preterm premature rupture of membranes: a randomised controlled trial.
      Conventional care for patients with PPROM included bed rest in the hospital and prophylactic antibiotic therapy in all studies. Five studies used tocolysis only when uterine contractions appeared without clinical chorioamnionitis or abruptio placenta
      • De Santis M.
      • Scavo M.
      • Noia G.
      • et al.
      Transabdominal amnioinfusion treatment of severe oligohydramnios in preterm premature rupture of membranes at less than 26 gestational weeks.
      • Gramellini D.
      • Fieni S.
      • Kaihura C.
      • Faiola S.
      • Vadora E.
      Transabdominal antepartum amnioinfusion.
      • Ogunyemi D.
      • Thompson W.
      A case controlled study of serial transabdominal amnioinfusions in the management of second trimester oligohydramnios due to premature rupture of membranes.
      • Vergani P.
      • Locatelli A.
      • Strobelt N.
      • et al.
      Amnioinfusion for prevention of pulmonary hypoplasia in second-trimester rupture of membranes.
      • Singla A.
      • Yadav P.
      • Vaid N.B.
      • Suneja A.
      • Faridi M.M.
      Transabdominal amnioinfusion in preterm premature rupture of membranes.
      ; however, 2 studies used tocolysis as a prophylactic measure for all patients, regardless of the presence of uterine contractions.
      • Garzetti G.G.
      • Ciavattini A.
      • De Cristofaro F.
      • La Marca N.
      • Arduini D.
      Prophylactic transabdominal amnioinfusion in oligohydramnios for preterm premature rupture of membranes: increase of amniotic fluid index during latency period.
      • Tranquilli A.L.
      • Giannubilo S.R.
      • Bezzeccheri V.
      • Scagnoli C.
      Transabdominal amnioinfusion in preterm premature rupture of membranes: a randomised controlled trial.
      Targeted antibiotic therapy based on cervical and vaginal cultures was used in 3 studies.
      • De Santis M.
      • Scavo M.
      • Noia G.
      • et al.
      Transabdominal amnioinfusion treatment of severe oligohydramnios in preterm premature rupture of membranes at less than 26 gestational weeks.
      • Garzetti G.G.
      • Ciavattini A.
      • De Cristofaro F.
      • La Marca N.
      • Arduini D.
      Prophylactic transabdominal amnioinfusion in oligohydramnios for preterm premature rupture of membranes: increase of amniotic fluid index during latency period.
      • Vergani P.
      • Locatelli A.
      • Strobelt N.
      • et al.
      Amnioinfusion for prevention of pulmonary hypoplasia in second-trimester rupture of membranes.
      Corticosteroids for fetal lung maturation was used after viability in all but 1 study.
      • Garzetti G.G.
      • Ciavattini A.
      • De Cristofaro F.
      • La Marca N.
      • Arduini D.
      Prophylactic transabdominal amnioinfusion in oligohydramnios for preterm premature rupture of membranes: increase of amniotic fluid index during latency period.
      The number of procedures per patient, success rate, and volumes infused varied among different studies and among different subjects in the same study. The average number of infusions per patient ranged from 1.23 in Singla et al
      • Singla A.
      • Yadav P.
      • Vaid N.B.
      • Suneja A.
      • Faridi M.M.
      Transabdominal amnioinfusion in preterm premature rupture of membranes.
      to 4.0 in De Santis et al.
      • De Santis M.
      • Scavo M.
      • Noia G.
      • et al.
      Transabdominal amnioinfusion treatment of severe oligohydramnios in preterm premature rupture of membranes at less than 26 gestational weeks.
      Vergani et al
      • Vergani P.
      • Locatelli A.
      • Strobelt N.
      • et al.
      Amnioinfusion for prevention of pulmonary hypoplasia in second-trimester rupture of membranes.
      reported a median number of 3 infusions per patient with a range of 1–9. Most of the studies did not report success rate; however, Garzetti et al
      • Garzetti G.G.
      • Ciavattini A.
      • De Cristofaro F.
      • La Marca N.
      • Arduini D.
      Prophylactic transabdominal amnioinfusion in oligohydramnios for preterm premature rupture of membranes: increase of amniotic fluid index during latency period.
      reported a success in 18 of 19 patients, and De Santis et al
      • De Santis M.
      • Scavo M.
      • Noia G.
      • et al.
      Transabdominal amnioinfusion treatment of severe oligohydramnios in preterm premature rupture of membranes at less than 26 gestational weeks.
      reported successful amnioinfusion in 143 of 147 procedures. The infused volumes range from 140-350 mL per infusion.
      • De Santis M.
      • Scavo M.
      • Noia G.
      • et al.
      Transabdominal amnioinfusion treatment of severe oligohydramnios in preterm premature rupture of membranes at less than 26 gestational weeks.
      • Garzetti G.G.
      • Ciavattini A.
      • De Cristofaro F.
      • La Marca N.
      • Arduini D.
      Prophylactic transabdominal amnioinfusion in oligohydramnios for preterm premature rupture of membranes: increase of amniotic fluid index during latency period.
      • Singla A.
      • Yadav P.
      • Vaid N.B.
      • Suneja A.
      • Faridi M.M.
      Transabdominal amnioinfusion in preterm premature rupture of membranes.
      • Tranquilli A.L.
      • Giannubilo S.R.
      • Bezzeccheri V.
      • Scagnoli C.
      Transabdominal amnioinfusion in preterm premature rupture of membranes: a randomised controlled trial.
      De Santis et al
      • De Santis M.
      • Scavo M.
      • Noia G.
      • et al.
      Transabdominal amnioinfusion treatment of severe oligohydramnios in preterm premature rupture of membranes at less than 26 gestational weeks.
      reported on 5 complications that occurred within 24 hours after infusion: 2 cord prolapses (1 cephalic and 1 transverse lie); 2 abruptio placentae, and 1 onset of labor. Gramellini et al
      • Gramellini D.
      • Fieni S.
      • Kaihura C.
      • Faiola S.
      • Vadora E.
      Transabdominal antepartum amnioinfusion.
      reported on a higher rate of vaginal bleeding in the intervention group (21%) compared with the nonamnioinfused group (7%), although this difference did not reach statistical significance. Ogunyemi and Thompson
      • Ogunyemi D.
      • Thompson W.
      A case controlled study of serial transabdominal amnioinfusions in the management of second trimester oligohydramnios due to premature rupture of membranes.
      reported on 2 neonatal complications that can be regarded as direct injuries from the procedure: 1 baby had a 2-cm leg laceration that was sutured, and 1 baby had a 0.5 × 0.5–cm superficial chest scar that needed no treatment.
      Assessment of the risk of bias in included observational cohort studies and RCTs are shown in TABLE 2, TABLE 3, respectively. The observational studies had minimal risk of bias, whereas 2 of 3 RCTs had moderate risk of bias, and 1 RCT had high risk of bias.
      TABLE 2Quality assessment of observational cohort studies by the Newcastle-Ottawa Scale system
      StudySelectionComparabilityOutcomeTotal stars, n
      Representativeness of the exposed cohortSelection of the nonexposed cohortAscertainment of exposureDemonstration that outcome of interest was not present at start of studyComparability of cohorts on the basis of the design or analysisAssessment of outcomeWas follow-up long enough for outcomes to occur?Adequacy of follow up of cohorts
      Ogunyemi and Thompson (2002)
      • Ogunyemi D.
      • Thompson W.
      A case controlled study of serial transabdominal amnioinfusions in the management of second trimester oligohydramnios due to premature rupture of membranes.
      *********9
      Vergani et al (1997)
      • Vergani P.
      • Locatelli A.
      • Strobelt N.
      • et al.
      Amnioinfusion for prevention of pulmonary hypoplasia in second-trimester rupture of membranes.
      *******7
      Garzetti et al (1997)
      • Garzetti G.G.
      • Ciavattini A.
      • De Cristofaro F.
      • La Marca N.
      • Arduini D.
      Prophylactic transabdominal amnioinfusion in oligohydramnios for preterm premature rupture of membranes: increase of amniotic fluid index during latency period.
      *********9
      Gramellini et al (2003)
      • Gramellini D.
      • Fieni S.
      • Kaihura C.
      • Faiola S.
      • Vadora E.
      Transabdominal antepartum amnioinfusion.
      *******7
      Each asterisk represents 1 star in the Newcastle-Ottawa Scale system. The maximum number of stars is 2 for comparability and 1 for each of the other categories.
      Porat. Transabdominal amnioinfusion for PPROM. Am J Obstet Gynecol 2012.
      TABLE 3Quality assessment of randomized controlled trials
      StudyBias
      SelectionPerformance: blinding of participants and personnelDetection: blinding of outcome assessmentAttrition: incomplete outcome dataReporting: selective reportingOther sourcesOverall
      Random sequence generationAllocation concealment
      Singla et al (2010)
      • Singla A.
      • Yadav P.
      • Vaid N.B.
      • Suneja A.
      • Faridi M.M.
      Transabdominal amnioinfusion in preterm premature rupture of membranes.
      Low riskUnclear riskUnclearUnclearLow riskLow riskLow riskModerate risk
      Tranquilli et al (2005)
      • Tranquilli A.L.
      • Giannubilo S.R.
      • Bezzeccheri V.
      • Scagnoli C.
      Transabdominal amnioinfusion in preterm premature rupture of membranes: a randomised controlled trial.
      Low riskLow riskUnclearUnclearLow riskLow riskLow riskModerate risk
      De Santis et al (2003)
      • De Santis M.
      • Scavo M.
      • Noia G.
      • et al.
      Transabdominal amnioinfusion treatment of severe oligohydramnios in preterm premature rupture of membranes at less than 26 gestational weeks.
      High riskHigh riskUnclearHigh riskLow riskLow riskLow riskHigh risk
      Porat. Transabdominal amnioinfusion for PPROM. Am J Obstet Gynecol 2012.

      Metaanalyses of observational studies

      Primary outcomes

      There was prolongation of the latency period (4 studies, 147 participants; mean difference, 14.4 days; 95% confidence interval [CI], 8.2–20.6 days; heterogeneity: I2 = 17%; Figure 2) and reduction in perinatal mortality rate (2 studies, 60 participants; pooled odds ratio [OR], 0.12; 95% CI, 0.02–0.61; heterogeneity: I2 = 0%; Figure 2). A subgroup analysis of periviable vs potentially viable babies could not be performed because of a lack of reporting data.
      Figure thumbnail gr2
      FIGURE 2Effect of serial TA on neonatal outcomes
      Forest plot of the results of the metaanalysis of observational studies for A, latency period length, which demonstrates the difference in latency period lengths between the TA and control groups; B, perinatal mortality rates refer to the odds ratio; and C, pulmonary hypoplasia refers to the odds ratio.
      TA, transabdominal amnioinfusion.
      Porat. Transabdominal amnioinfusion for PPROM. Am J Obstet Gynecol 2012.

      Secondary outcomes

      Results of metaanalyses of secondary outcomes are given in Table 4. There were a decreased rate of pulmonary hypoplasia (2 studies, 45 participants; pooled OR, 0.17; 95% CI, 0.04–0.78; heterogeneity: I2 = 0%; Figure 2) and a reduced risk for neonatal death (1 study, 18 participants; OR, 0.09; 95% CI, 0.01–0.84; heterogeneity: not applicable). The other tested secondary outcomes did not reach statistical significance.
      TABLE 4Effect of transabdominal amnioinfusion on the tested outcomes
      Studied outcomeMetaanalysis of observational studiesMetaanalysis of randomized controlled trials
      Studies/participants, nEffect estimate
      Data are given as odds ratio (95% confidence interval);
      Studies/participants, nEffect estimate
      Data are given as odds ratio (95% confidence interval);
      Difference in mean gestational age at preterm premature rupture of membranes, d
      The first 4 rows of data represent mean difference with 95% confidence interval, the rest of the rows represent odds ratio with 95% confidence interval.
      4/147−12.30 (−18.56 to −6.03)3/165−1.58 (−8.09 to 4.52)
      Difference in mean gestational age at delivery, d
      The first 4 rows of data represent mean difference with 95% confidence interval, the rest of the rows represent odds ratio with 95% confidence interval.
      3/111−4.11 (−22.23 to 14.00)3/1653.86 (−16.49 to 24.21)
      Difference in mean latency period length, d
      The first 4 rows of data represent mean difference with 95% confidence interval, the rest of the rows represent odds ratio with 95% confidence interval.
      4/14714.40 (8.24–20.56)3/16511.41 (−3.36 to 26.18)
      Difference in mean birthweight, g
      The first 4 rows of data represent mean difference with 95% confidence interval, the rest of the rows represent odds ratio with 95% confidence interval.
      2/77−129.52 (−691.09 to 432.06)3/165125.00 (−105.68 to 355.68)
      Perinatal mortality rate2/600.12 (0.02–0.61)2/1310.33 (0.10–1.12)
      Pulmonary hypoplasia2/450.17 (0.04–0.78)2/690.30 (0.05–1.70)
      Amnionitis/endometritis3/1110.94 (0.33–2.68)2/1310.28 (0.11–0.69)
      Early onset sepsis1/180.10 (0.00–2.35)2/830.38 (0.02–6.07)
      Neonatal mortality rate1/180.09 (0.01–0.84)3/1290.52 (0.07–3.76)
      Bronchopulmonary dysplasia1/182.14 (0.08–60.17)1/207.67 (0.32–183.01)
      Genitourinary infectionN/AN/A1/711.29 (0.49–3.42)
      Cesarean delivery2/544.16 (0.96–17.95)1/712.35 (0.81–6.81)
      N/A, not applicable.
      Porat. Transabdominal amnioinfusion for PPROM. Am J Obstet Gynecol 2012.
      a Data are given as odds ratio (95% confidence interval);
      b The first 4 rows of data represent mean difference with 95% confidence interval, the rest of the rows represent odds ratio with 95% confidence interval.

      Metaanalyses of RCTs

      Primary outcomes

      There was no statistically significant difference in the latency period (3 studies, 165 participants; mean difference, 11.4 days increase in latency in TA group; however, 95% CI −3.4 to 26.2 days; heterogeneity: I2 = 89%; Figure 3) and no statistically significant difference in perinatal mortality rate (2 studies, 131 participants; pooled OR, 0.33; 95% CI, 0.10–1.12; heterogeneity: I2 = 45%; Figure 3). A subgroup analysis of periviable vs potentially viable babies could not be performed because of a lack of reporting data.
      Figure thumbnail gr3
      FIGURE 3Effect of serial TA on neonatal outcomes for randomized controlled trials
      Forest plot of the results of the metaanalysis of randomized controlled trials for A, latency period length, which demonstrates the difference in latency period lengths between the TA and control groups; B, perinatal mortality rates refer to the odds ratio; and C, pulmonary hypoplasia refers to odds ratio.
      TA, transabdominal amnioinfusion.
      Porat. Transabdominal amnioinfusion for PPROM. Am J Obstet Gynecol 2012.

      Secondary outcomes

      Results of metaanalyses of secondary outcomes are given in Table 4. There was no statistically significant difference in the rate of pulmonary hypoplasia (2 studies, 69 participants; pooled OR, 0.3; 95% CI, 0.05–1.7; heterogeneity: I2 = 52%; Figure 3).
      Interestingly, there was a decreased rate of infectious complications of amnionitis or chorioamnionitis in the TA group (2 studies, 131 participants; OR, 0.28; 95% CI, 0.11–0.69; heterogeneity: I2 = 0%). None of the other secondary outcomes reached statistical significance.

      Comment

      Mid-trimester PPROM poses a challenging clinical problem. Poor prognosis usually results from the combination of prematurity, pulmonary hypoplasia, and infection. The prognosis of mid-trimester PPROM at <21 weeks of gestation is grave because most fetuses experience pulmonary hypoplasia.
      • Deutsch A.
      • Deutsch E.
      • Totten C.
      • Downes K.
      • Haubner L.
      • Belogolovkin V.
      Maternal and neonatal outcomes based on the gestational age of midtrimester preterm premature rupture of membranes.
      Pregnancy outcomes are correlated directly with the gestational age at which the membranes are ruptured and the amount of residual fluid after the rupture of membranes. Low residual volume of amniotic fluid has been shown to be associated with a shorter latency period
      • Vermillion S.T.
      • Kooba A.M.
      • Soper D.E.
      Amniotic fluid index values after preterm premature rupture of the membranes and subsequent perinatal infection.
      • Coolen J.
      • Kabayashi K.
      • Wong K.
      • Mayes D.C.
      • Bott N.
      • Demianczuk N.
      Influence of oligohydramnios on preterm premature rupture of the membranes at 30 to 36 weeks' gestation.
      and increased risk for early onset neonatal sepsis and chorioamnionitis.
      • Vermillion S.T.
      • Kooba A.M.
      • Soper D.E.
      Amniotic fluid index values after preterm premature rupture of the membranes and subsequent perinatal infection.
      Lack of an effective treatment or intervention to prolong pregnancy complicates this situation even further. Despite the seriousness and gravity of this condition, current obstetrics management has little to offer. Aside from close monitoring for signs of infection or early labor, no obstetrics interventions have demonstrated the ability to reduce morbidity or mortality rate that is the result of early PPROM or specifically to address the pathophysiologic processes that underlie the cause of this condition.
      In this metaanalysis, a better short-term prognosis in women with PPROM who underwent serial TA was seen in the observational studies. The intervention group had significant latency prolongation and improved perinatal and neonatal survival and experienced less pulmonary hypoplasia. These results intensify in the face of significantly lower gestational age at rupture of membranes in the intervention group, compared with the control group in the observational studies (12.3 days of difference; 95% CI, 6.03–18.56). The results from the metaanalysis of RCTs demonstrated a trend toward benefit, but the results were not statistically significant. This is possibly because of the small number of participants in the studies and the lack of power.
      The hypothesis is that infectious/inflammatory processes are responsible for the activation of the laboring process. Thus, the theoretic benefit of amnioinfusion or the introduction of physiologic solution into the amniotic cavity includes (1) washout/dilution of preexisting intraamniotic bacteria, (2) washout/dilution of inflammatory cells and mediators (prostaglandins, leukotrienes, cytokines, interleukins among others), and (3) increase in intraamniotic fluid volume and pressure. Theoretically, washing out or diluting the preexisting intraamniotic bacteria and inflammatory cells may be beneficial to prolong the latent period, and the presence of fluid may promote lung development and prevent positional contractures. There are also potential secondary benefits from this intervention that include the ability to test fetal genetics (when indicated), an improvement in ultrasound imaging of the baby, and a decreased risk for cord compression.
      The strengths of this metaanalysis, compared with the recently published Cochrane review,
      • Hofmeyr G.J.
      • Essilfie-Appiah G.
      • Lawrie T.A.
      Amnioinfusion for preterm premature rupture of membranes.
      include a larger sample size, the inclusion of observational and RCT data that give the full picture of this intervention, and the assessment of all clinically important outcomes. The results indicate a potentially beneficial effect for the intervention. However, because of the small sizes of included randomized studies and our inability to conclude with confidence because of lack of power, we suggest large adequately powered studies are needed for this intervention. Because of the rarity of the condition, we suggest that a multicenter collaboration with standardization of treatment for such women will allow adequate power and generalizability of findings. Limitations of this review include the low numbers of participants both in the observational studies and the RCTs. In addition, in regards to the protocol and assessment of outcomes, there was heterogeneity in the reporting of the included studies. Finally, there was heterogeneity in the quality of the studies in terms of risk of bias.
      If the superiority of serial TA over conservative management is confirmed by further studies, this directly would impact both the management and research of early PPROM. First, this intervention could be offered to couples who face the grim situation in which no other interventions are available. Second, it will enable further research into the contribution of the amount and the constitution of amniotic fluid for lung development at different fetal developmental stages. It will raise questions in regards to the lower threshold of amniotic fluid volume or pressure that supports lung development, which is the role of amniotic fluid turnover and the role of amniotic fluid.
      This metaanalysis suggests that serial TA improved pregnancy outcomes when tested in observational studies, but not in RCTs; however, for both types of studies, the number of patients that were included remains very small. These results warrant a large, multicenter RCT to investigate the usefulness of such an intervention in a hospital-based setting.

      Acknowledgment

      We thank Ms Elizabeth Uleryk, Chief Librarian at the Hospital for Sick Children, Toronto, Canada, for her contribution in developing the search strategies and for running the search on a periodic basis.

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