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Outpatient endometrial aspiration: an alternative to methotrexate for pregnancy of unknown location

Published:April 19, 2017DOI:https://doi.org/10.1016/j.ajog.2017.04.023

      Background

      Pregnancies of unknown location with abnormal beta-human chorionic gonadotropin trends are frequently treated as presumed ectopic pregnancies with methotrexate. Preliminary data suggest that outpatient endometrial aspiration may be an effective tool to diagnose pregnancy location, while also sparing women exposure to methotrexate.

      Objective

      The purpose of this study was to evaluate the utility of an endometrial sampling protocol for the diagnosis of pregnancies of unknown location after in vitro fertilization.

      Study Design

      A retrospective cohort study of 14,505 autologous fresh and frozen in vitro fertilization cycles from October 2007 to September 2015 was performed; 110 patients were diagnosed with pregnancy of unknown location, defined as a positive beta-human chorionic gonadotropin without ultrasound evidence of intrauterine or ectopic pregnancy and an abnormal beta-human chorionic gonadotropin trend (<53% rise or <15% fall in 2 days). These patients underwent outpatient endometrial sampling with Karman cannula aspiration. Patients with a beta-human chorionic gonadotropin decline ≥15% within 24 hours of sampling and/or villi detected on pathologic analysis were diagnosed with failing intrauterine pregnancy and had weekly beta-human chorionic gonadotropin measurements thereafter. Those patients with beta-human chorionic gonadotropin declines <15% and no villi identified were diagnosed with ectopic pregnancy and treated with intramuscular methotrexate (50 mg/m2) or laparoscopy.

      Results

      Across 8 years of follow up, among women with pregnancy of unknown location, failed intrauterine pregnancy was diagnosed in 46 patients (42%), and ectopic pregnancy was diagnosed in 64 patients (58%). Clinical variables that included fresh or frozen embryo transfer, day of embryo transfer, serum beta-human chorionic gonadotropin at the time of sampling, endometrial thickness, and presence of an adnexal mass were not significantly different between patients with failed intrauterine pregnancy or ectopic pregnancy. In patients with failed intrauterine pregnancy, 100% demonstrated adequate postsampling beta-human chorionic gonadotropin declines; villi were identified in just 46% (n=21 patients). Patients with failed intrauterine pregnancy had significantly shorter time to resolution (negative serum beta-human chorionic gonadotropin) after sampling compared with patients with ectopic pregnancy (12.6 vs 26.3 days; P<.001).

      Conclusion

      With the use of this safe and effective protocol of endometrial aspiration with Karman cannula, a large proportion of women with pregnancy of unknown location are spared methotrexate, with a shorter time to pregnancy resolution than those who receive methotrexate.

      Key words

      Pregnancy of unknown location (PUL) is diagnosed in women with positive beta-human chorionic gonadotropin (hCG) in the absence of ultrasound evidence of an intrauterine pregnancy (IUP) or ectopic pregnancy.
      • Barnhart K.T.
      • Sammel M.D.
      • Rinaudo P.F.
      • Zhou L.
      • Hummel A.C.
      • Guo W.
      Symptomatic patients with an early viable intrauterine pregnancy.
      Up to 30% of PULs will develop into intrauterine pregnancies; the remainder will be diagnosed as spontaneous abortions or ectopic pregnancies.
      • Kirk E.
      Pregnancies of unknown location.
      Ectopic pregnancy occurs in approximately 1.3–2% of spontaneously conceived pregnancies.
      • Farquhar C.M.
      Ectopic Pregnancy.
      Historically, pregnancies conceived with assisted reproductive technologies (ART) have been associated with an increased risk of ectopic pregnancy; a recent review of 10 years of data from the National ART Surveillance System reported an ectopic pregnancy rate as low as 1.7%, similar to the ectopic pregnancy rate in the general population.
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      Ectopic Pregnancy.
      • Perkins K.M.
      • Boulet S.L.
      • Kissin D.M.
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      Risk of ectopic pregnancy associated with assisted reproductive technology in the United States, 2001-2011.
      Ectopic pregnancies are a leading cause of maternal morbidity and death because they carry a risk of rupture, internal hemorrhage, and death.
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      • Boulet S.L.
      • Kissin D.M.
      • Jamieson D.J.
      Risk of ectopic pregnancy associated with assisted reproductive technology in the United States, 2001-2011.
      Most research to date has focused on early diagnosis to avoid these complications. In patients with PUL, concern for ectopic pregnancy is compounded by the presence of an abnormal hCG trend, which has been defined as an increase <53% or a decrease <15% over 48 hours.
      • Barnhart K.T.
      • Sammel M.D.
      • Rinaudo P.F.
      • Zhou L.
      • Hummel A.C.
      • Guo W.
      Symptomatic patients with an early viable intrauterine pregnancy.
      At many institutions, PULs with abnormal hCG trends are presumed to be ectopic pregnancies; thus, medical therapy with the chemotherapeutic agent methotrexate is commonly used.
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      Early pregnancy failure: beware of the pitfalls of modern management.
      Methotrexate is a folic acid antagonist that acts by interfering with DNA synthesis and cell proliferation in highly metabolically active cells, such as trophoblasts. Rarely, low-dose methotrexate can be associated with significant toxicity for the patient, including nausea, vomiting, rashes, alopecia, impaired liver function, stomatitis, conjunctivitis, and bone marrow suppression, although usually in higher doses.
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      Finally, because of the potential teratogenic effects after methotrexate exposure, women are counseled to wait up to 3 months before attempting to conceive, which represents a frustrating delay in care for many patients.
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      Aspiration of endometrial contents to diagnose pregnancy location definitively is an alternative to presumptive methotrexate administration. Historically, endometrial sampling for this purpose has involved dilation in an operating room with anesthesia and associated increases in time, cost, and potential anesthetic morbidity.
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      Utility of dilation and curettage in the diagnosis of pregnancy of unknown location.
      Sampling with a standard endometrial biopsy pipelle (commonly used for diagnosis of endometrial hyperplasia or carcinoma) has low sensitivity for the detection of chorionic villi, which ranges from 13–63%, and has not yet been evaluated in conjunction with post-biopsy serum hCG levels.
      • Barnhart K.T.
      • Gracia C.R.
      • Reindl B.
      • Wheeler J.E.
      Usefulness of pipelle endometrial biopsy in the diagnosis of women at risk for ectopic pregnancy.
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      A minimally invasive approach to aspiration of endometrial tissue in the outpatient office setting for the diagnosis of pregnancy location has also been described with the use of several products, which includes the Karman cannula (WomenCare Global LLC, Chapel Hill, NC) attached to a handheld suction device Figure 1).
      • Suarez R.A.
      • Grimes D.A.
      • Majmudar B.
      • Benigno B.B.
      Diagnostic endometrial aspiration with the Karman cannula.
      • Brady P.
      • Imudia A.N.
      • Awonuga A.O.
      • Wright D.L.
      • Styer A.K.
      • Toth T.L.
      Pregnancies of unknown location after in vitro fertilization: minimally invasive management with Karman cannula aspiration.

      WomanCare Global Aspirator and Cannula Line [Internet]. [cited 2016 Dec 27]. Available at: http://www.womancareglobal.org/wp-content/uploads/2012/08/MVA_Product_Line_A4.pdf. Accessed December 15, 2016.

      The office procedure requires no anesthesia other than an optional paracervical block with local anesthetic and is well tolerated.
      Figure thumbnail gr1
      Figure 1Karman cannulas of varying diameters
      The cannulas are manufactured and distributed by WomenCare Global LLC, Chapel Hill, NC.

      WomanCare Global Aspirator and Cannula Line [Internet]. [cited 2016 Dec 27]. Available at: http://www.womancareglobal.org/wp-content/uploads/2012/08/MVA_Product_Line_A4.pdf. Accessed December 15, 2016.

      The cannula is attached to a handheld manual vacuum aspirator device for endometrial sampling in an outpatient setting.
      Insogna et al. Karman biopsy to diagnose pregnancy location. Am J Obstet Gynecol 2017.
      A recent study of 44 women with PUL after in vitro fertilization (IVF) reported that endometrial aspiration with the Karman cannula allowed two-thirds of patients to avoid methotrexate administration.
      • Brady P.
      • Imudia A.N.
      • Awonuga A.O.
      • Wright D.L.
      • Styer A.K.
      • Toth T.L.
      Pregnancies of unknown location after in vitro fertilization: minimally invasive management with Karman cannula aspiration.
      This study demonstrated the utility of a Karman aspiration protocol as an effective diagnostic tool for women with PUL suspicious for ectopic pregnancy. We sought to confirm the utility of the Karman cannula aspiration protocol in a larger sample size, hypothesizing that, by using this protocol, a significant proportion of women with PUL after IVF would be spared methotrexate exposure, with faster resolution to a negative hCG level. The IVF population is ideal for testing this endometrial sampling protocol, given the exact pregnancy dating, detailed reproductive data available for each patient, and close outpatient follow up. Additionally, we sought to identify clinical parameters that are predictive of ectopic pregnancy among patients with PUL and abnormal hCG trends, which may be useful in patient selection and counseling for all women with PUL, regardless of their use of ART.

      Materials and Methods

      Before beginning data collection, the protocol for this retrospective cohort study was approved by the Partners Healthcare Institutional Review Board. Using the prospectively maintained IVF database of the Brigham and Women’s Center for Infertility and Reproductive Surgery, fresh and frozen autologous IVF cycles from October 2007 to September 2015 were reviewed (n=14,505). Because this was a retrospective review that used de-identified patient data, the need for individual patient consent was waived. All data were reviewed for correctness and verified directly in the clinical electronic medical record.
      Stimulation protocols for fresh cycles included ones that used gonadotropin-releasing hormone antagonists, down-regulation with the use of gonadotropin-releasing hormone agonists, and estradiol priming or low-dose gonadotropin-releasing hormone agonist flare protocols for poor responders.
      • Cheung L.-P.
      • Lam P.-M.
      • Lok I.H.
      • et al.
      GnRH antagonist versus long GnRH agonist protocol in poor responders undergoing IVF: a randomized controlled trial.
      • Tummon I.S.
      • Daniel S.A.
      • Kaplan B.R.
      • Nisker J.A.
      • Yuzpe A.A.
      Randomized, prospective comparison of luteal leuprolide acetate and gonadotropins versus clomiphene citrate and gonadotropins in 408 first cycles of in vitro fertilization.
      • Surrey E.S.
      • Bower J.
      • Hill D.M.
      • Ramsey J.
      • Surrey M.W.
      Clinical and endocrine effects of a microdose GnRH agonist flare regimen administered to poor responders who are undergoing in vitro fertilization.
      • Dragisic K.G.
      • Davis O.K.
      • Fasouliotis S.J.
      • Rosenwaks Z.
      Use of a luteal estradiol patch and a gonadotropin-releasing hormone antagonist suppression protocol before gonadotropin stimulation for in vitro fertilization in poor responders.
      Both natural and programmed protocols were used for frozen cycles, with a goal endometrial thickness by ultrasound scan of 7 mm. The embryo transfer day and number were determined by laboratory protocols, with the proportion of blastocyst transfers increasing over the study time period. All embryo transfers were performed with a soft Wallace catheter under ultrasound guidance.
      PUL was defined as a positive hCG level (≥3 IU/L) and ultrasound scan without evidence of IUP or ectopic pregnancy. Initial hCG levels were drawn 7–18 days after embryo transfer (median, 13 days). Before undergoing Karman aspiration, all patients demonstrated an abnormal hCG trend (<53% rise or <15% fall in 2 days), over a minimum of 3 hCG measurements. HCG levels were checked at the time of Karman aspiration and within 24 hours after the procedure. Patients with an hCG level decline ≥15% within 24 hours of sampling and/or villi detected on pathologic analysis were diagnosed with failing IUP and had weekly hCG measurements thereafter. Patients with hCG level declines <15% and no villi identified on pathology report were diagnosed with presumed ectopic pregnancy and treated with intramuscular methotrexate (50 mg/m2) or laparoscopy. Methotrexate was the standard treatment, unless patients had acute abdominal pain suggestive of ruptured ectopic pregnancy or declined medical treatment, in which case laparoscopy was performed. In patients receiving methotrexate, hCG levels were checked 4 and 7 days after methotrexate administration, with up to 3 additional doses of methotrexate given if the hCG level did not decline by at least 15% between days 4 and 7 after each dose.
      The Karman cannula aspiration protocol was performed in the outpatient setting without sedation. The patient was counseled and consented before the procedure. The patient was placed in the lithotomy position; a speculum was inserted, and the cervix was prepped with betadine. According to provider and patient preference, patients could receive a paracervical block of 10–20 mL of 1% lidocaine. The anterior lip of the cervix was grasped with a single-toothed tenaculum. A Karman cannula that ranged from 3–6 mm in width, depending on clinician preference, that attached to a handheld manual vacuum aspiration device was passed into the uterus and advanced to the fundus; endometrial contents were then aspirated. No cervical dilation was required in any patients. The tissue was sent in sterile saline solution to the Pathology Department for permanent fixation and review of serial sections that were stained with hematoxylin and eosin; frozen sections or gross analysis by floating endometrial samples in saline solution was not performed. Pathologic results were available within 24 hours, at which point patients had also returned for a repeat serum hCG level.
      The hCG measurements were performed at the Brigham and Women’s clinical laboratory, inspected by the Joint Commission with Clinical Laboratory Improvement Amendments (CLIA) certification. The electrochemiluminescence immunoassay was run using the Cobas e601 platform (Roche Diagnostics, Mannheim, Germany). Inter- and intraassay coefficients of variation for the assay were <5.5%, and results were standardized against the fourth International Standard for Chorionic Gonadotropin from the National Institute for Biological Standards and Control 75/589.

      Jerne, Perry, Storring PL, Das G, Bangham RD. WHO International Standard 4th IS Chorionic Gonadotropin, Human NIBSC code: 75/589 Instructions for use. Bull World Heal Organ Kirkwood TBL Biometrics J Endocrinol Acta Endocrinol WHO Expert Comm Biol Stand WHO Expert Comm Biol Stand 1956;14:167-82.

      The 2-day rise in early hCG level was calculated for patients whose hCG levels were not drawn exactly 2 days apart with the use of the log-linear nature of early hCG level rises.
      • Barnhart K.T.
      • Sammel M.D.
      • Rinaudo P.F.
      • Zhou L.
      • Hummel A.C.
      • Guo W.
      Symptomatic patients with an early viable intrauterine pregnancy.
      The difference between the first and second hCG levels log values was divided by the log of the first value; this percent increase in log hCG level subsequently was divided by the number of days between the first and second measurements and multiplied by 2. This value was exponentiated to yield an absolute hCG value, from which the 2-day percent hCG level rise was calculated.
      Multivariable logistic regression was used to calculate odds ratios and 95% confidence intervals (CI) of the association between demographic and cycle characteristics and pregnancy location. Oocyte age was included in the model a priori as a potential confounder. Covariates tested as primary exposures and also as potential confounders of this relationship included recipient age at the time of embryo transfer, recipient gravidity and parity, previous ectopic pregnancy, previous miscarriage, infertility diagnosis, day-3 follicle-stimulating hormone level, body mass index, fresh vs frozen cycle, stimulation protocol, use of intracytoplasmic sperm injection, use of assisted hatching, day of embryo transfer, number of embryos transferred, number of good-quality embryos transferred, endometrial stripe thickness at the time of the first ultrasound scan after embryo transfer, presence of an adnexal mass or free fluid by ultrasound scan, initial and peak hCG levels, and gestational age and serum hCG level at the time of Karman aspiration.
      A history of ectopic pregnancy or miscarriage, infertility diagnosis, fresh vs frozen cycle, use of assisted hatching, use of intracytoplasmic sperm injection, day of embryo transfer (day 3 or 5), the presence of an adnexal mass or free fluid were included as dichotomous or categoric variables. Recipient and oocyte age (years), body mass index (kilograms per square meter), gravidity, parity, number of embryos transferred, number of good-quality embryos transferred, laboratory values, gestational ages, endometrial stripe thickness (millimeter), and dimensions of adnexal masses (millimeter) were included as continuous variables. Good quality cleavage-stage embryos were defined as having ≥7 cells, <9% fragmentation, and perfect or moderate asymmetry.
      • Men C.J.
      • Bormann C.L.
      • Walsh B.W.
      • Racowsky C.
      Is the presence of an uncleaved embryo on day 3 a useful predictor of outcomes following day 5 transfer?.
      Good-quality blastocysts were defined as hatched or hatching blastocysts with fair or good-quality trophectoderm and inner cell mass.
      • Gardner D.K.
      • Schoolcraft W.B.
      Culture and transfer of human blastocysts.
      Variables that, on addition to the regression model, changed the odds ratios for the base model covariates by ≥10% were retained in the final adjusted model; however, no additional variables met this condition.
      • Mickey R.M.
      • Greenland S.
      The impact of confounder selection criteria on effect estimation.
      Similarly, a linear regression model that was adjusted a priori for hCG level at the time of Karman aspiration was used to calculate the linear regression estimate of the association between IUP or ectopic pregnancy and the number of days from Karman aspiration until negative hCG level. Analyses were performed with Statistical Analysis Software (version 9.3; SAS Institute, Inc, Cary, NC).

      Results

      Among the 14,505 IVF cycles completed from October 2007 to September 2015, cycles that resulted in no pregnancy, spontaneous abortion, and ongoing IUPs were excluded (n=12,991). The remaining 1514 IVF cycles were categorized as either ectopic pregnancies or chemical pregnancies. From these cycles, we identified 135 patients who underwent Karman aspiration before their final categorization. Several patients underwent Karman aspiration in ≥2 unique cycles within the study time frame (n=20); only the initial cycle with a Karman aspiration within the time frame was included.
      Five patients whose care deviated from the defined protocol, according to clinician preference, were excluded. One patient received methotrexate despite an adequate decline in hCG level after the Karman protocol; 3 patients did not receive methotrexate despite inadequate hCG level declines after the Karman protocol. Of note, all 3 of these patients had very low hCG levels (15–44 IU/L), which spontaneously resolved to zero. One patient did not have an hCG level checked 24 hours after the Karman aspiration and received methotrexate. A total of 110 patients were included in the final study. Table 1 includes demographic and cycle characteristics for women with failed IUP and women with EP.
      Table 1Demographic and cycle characteristics in patients with failed intrauterine pregnancy and ectopic pregnancy
      CharacteristicsFailed intrauterine pregnancy (n=46)Ectopic pregnancy (n=64)
      Patient age, y
      Data are given as mean±standard deviation.
      37.6±3.736.8±3.8
      Body mass index, kg/m2
      Data are given as mean±standard deviation.
      25.6±6.227.3±7.9
      Gravidity, n
      Data are given as mean±standard deviation.
      1.3±1.21.0±1.3
      Parity, n
      Data are given as mean±standard deviation.
      0.4±0.60.2±0.4
      Previous ectopic pregnancy, n (%)4 (8.7)7 (10.9)
      Previous miscarriage, n (%)19 (41.3)17 (26.6)
      Infertility diagnosis, n (%)
       Endometriosis04 (6.3)
       Diminished ovarian reserve6 (13.0)10 (15.6)
       Male factor10 (21.7)20 (31.3)
       Ovulatory dysfunction7 (15.2)11 (17.2)
       Tubal infertility4 (8.7)9 (14.1)
       Unknown infertility23 (50.0)16 (25.0)
       Uterine factor01 (1.6)
      Fresh cycle, n (%)41 (89.1)55 (85.9)
      Intracytoplasmic sperm injection, n (%)15 (32.6)27 (42.2)
      Assisted hatching, n (%)31 (67.3)33 (51.6)
      Day 3 embryo transfer, n (%)37 (80.4)49 (76.6)
      Embryos transferred, n
      Data are given as mean±standard deviation.
      2.5±1.12.4±1.2
      “Good-quality” embryos transferred, n
      Data are given as mean±standard deviation.
      1.5±1.20.9±1.1
      Day of initial beta-human chorionic gonadotropin after embryo transfer, IU/L
      Data are given as mean±standard deviation.
      12.8±1.512.7±1.5
      Initial beta-human chorionic gonadotropin, IU/L
      Data are given as mean±standard deviation.
      83.5±93.263.4±77.4
      Mean percentage of change between first and second beta-human chorionic gonadotropin levels
      Data are given as mean±standard deviation.
      13.7±27.513.7±37.4
      Karman cannula diameter in millimeters, mm
      Data are given as mean±standard deviation.
      4.3±0.64.1±0.5
      Total number of beta-human chorionic gonadotropin levels before Karman
      Data are given as mean±standard deviation.
      4.6±1.45.9±2.1
      Peak beta-human chorionic gonadotropin
      Data are given as mean±standard deviation.
      477.2±930.2888.64±1600.8
      Endometrial thickness on first ultrasound after ectopic pregnancy, mm
      Data are given as mean±standard deviation.
      10.3±2.610.5±3.0
      Gestational age at time of first ultrasound scan, wk
      Data are given as mean±standard deviation.
      5.38±0.415.6±0.6
      Adnexal mass present on ultrasound, n (%)10 (24.4)18 (29.0)
      Size of adnexal mass, cm
      Data are given as mean±standard deviation.
      2.0±1.21.6±0.9
      Presence of free fluid, n (%)6 (14.6)8 (12.9)
      Beta-human chorionic gonadotropin at time of Karman, IU/L
      Data are given as mean±standard deviation.
      439.5±905.1628.1±1324.1
      Gestational age at time of Karman, wk
      Data are given as mean±standard deviation.
      5.5±0.66.0±0.7
      Beta-human chorionic gonadotropin at initial methotrexate administration, IU/L
      Data are given as mean±standard deviation.
      NA433.2±798.1
      Gestational age at time of methotrexate, wk
      Data are given as mean±standard deviation.
      NA6.1±0.8
      Doses of methotrexate required
      Data are given as mean±standard deviation.
      NA1.2±0.7
      Good quality cleavage-stage embryos: ≥7 cells, <9% fragmentation, perfect or moderate asymmetry. Good quality blastocysts: hatched or hatching blastocysts with fair- or good-quality trophectoderm and inner cell mass.
      Insogna et al. Karman biopsy to diagnose pregnancy location. Am J Obstet Gynecol 2017.
      a Data are given as mean±standard deviation.
      The mean initial hCG level was 71.8 IU/L. A second hCG level was checked 2–4 days after the initial level (mean value, 2.4 days). The mean number of hCG levels collected before Karman aspiration was 4.6 in the failed IUP group and 5.9 in the ectopic pregnancy group. Karman aspiration was performed at approximately 5.5 and 6.0 weeks gestational age for the failed IUP and ectopic pregnancy groups, respectively, with mean hCG levels of 440 IU/L (range, 13–6073 IU/L) and 628 IU/L (range, 14–6667 IU/L), respectively, at the time of the procedure.
      Failed IUPs were diagnosed in 46 patients (41.8%), and presumed ectopic pregnancies were diagnosed in 64 patients (58.2% of PULs, and 0.4% of all autologous IVF cycles; Figure 2. An additional 64 patients in our practice during this time period were treated for ectopic pregnancy based on ultrasound or clinical findings without endometrial aspiration, for a total ectopic pregnancy rate of 0.8% over this time period.
      Figure thumbnail gr2
      Figure 2Diagnostic outcomes
      Diagnostic outcomes after endometrial aspiration with Karman cannula for pregnancy of unknown location are given. Pregnancy of unknown location was defined as a serum beta-human chorionic gonadotropin ≥3 IU/L without ultrasound evidence of intrauterine or ectopic pregnancy. An abnormal beta-human chorionic gonadotropin trend was defined as a rise of <53% or a fall of <15% in 2 days. Ectopic pregnancy was diagnosed after endometrial sampling by serum beta-human chorionic gonadotropin decline of <15% and failure to identify villi on pathologic analysis.
      Insogna et al. Karman biopsy to diagnose pregnancy location. Am J Obstet Gynecol 2017.
      As shown in Table 2, no statistically significant differences were identified in any cycle or demographic characteristic between the 2 groups, including whether fresh vs frozen embryos or cleavage-stage embryos vs blastocysts were transferred, serum hCG level at the time of sampling, endometrial thickness on ultrasound scan (measured on the day of hCG trigger in fresh cycles, and at the time of progesterone start in cryopreserved cycles), or the presence of an adnexal mass on ultrasound scan (performed an average of 21.4 days after embryo transfer). Neither a history of ectopic pregnancy nor tubal factor infertility demonstrated statistically significant associations with ectopic pregnancy (odds ratios, 1.26 [95% CI, 0.34–4.60] and 1.70 [95% CI, 0.49–5.91], respectively).
      Table 2Predictors of ectopic pregnancy after endometrial aspiration with Karman cannula
      CharacteristicsFailed intrauterine pregnancy (n=46)Ectopic pregnancy (n=64)Adjusted odds ratio of ectopic pregnancy (95% confidence interval)
      Adjusted for patient age
      Patient age, y
      Data are given as mean±standard deviation.
      37.6±3.736.8±3.80.95 (0.86–1.05)
      Body mass index, kg/m2
      Data are given as mean±standard deviation.
      25.6±6.227.3±7.91.03 (0.98–1.09)
      Previous ectopic pregnancy, n (%)4 (8.7)7 (10.9)1.26 (0.34–4.60)
      Tubal factor infertility, n (%)4 (8.7)9 (14.1)1.70 (0.49–5.91)
      Cryopreserved embryo cycle, n (%)5 (8.7)9 (14.1)1.23 (0.38–4.03)
      Day 3 embryo transfer, n (%)37 (80.3)49 (76.6)0.83 (0.33–2.12)
      Embryos transferred, n
      Data are given as mean±standard deviation.
      2.5±1.12.1±1.20.97 (0.66–1.42)
      First beta-human chorionic gonadotropin, IU/L
      Data are given as mean±standard deviation.
      83.5±93.263.4±77.40.76 (0.47–1.22)
      Beta-human chorionic gonadotropin at time of Karman, IU/L
      Data are given as mean±standard deviation.
      439.5±905.0628.1±1324.11.01 (0.98–1.05)
      Endometrial thickness on first ultrasound after embryo transfer, mm
      Data are given as mean±standard deviation.
      10.3±2.610.5±2.91.04 (0.91–1.20)
      Adnexal mass on ultrasound, n (%)10 (21.7)18 (29.0)1.28 (0.52–3.15)
      Size of adnexal mass on ultrasound, cm
      Data are given as mean±standard deviation.
      2.0±1.21.5±0.90.45 (0.16–1.23)
      Insogna et al. Karman biopsy to diagnose pregnancy location. Am J Obstet Gynecol 2017.
      a Adjusted for patient age
      b Data are given as mean±standard deviation.
      Forty-two percent of the women (46/110) in the study were spared exposure to methotrexate by the use of this protocol. Of the 46 patients who were diagnosed with a failed IUP, 100% had appropriate hCG level decline of at least 15% within 24 hours after the Karman aspiration. Just 21 of these 46 patients (45.6%) had chorionic villi confirmed by pathologic evidence; the remaining 25 patients (54.3%) had no villi identified and were diagnosed as having a failed IUP by the declining hCG level alone. Weekly hCG levels were followed until undetectable in all patients who were diagnosed with failed IUP.
      Three patients who initially were categorized as failed IUPs by postprocedure hCG level decline alone (with no villi identified on pathologic analysis) had subsequent plateaus and/or rises of their weekly serum hCG measurements during the surveillance period. All 3 of these women ultimately were diagnosed with presumed ectopic pregnancy and received a single dose of methotrexate, with adequate decline of their serum hCG level thereafter.
      Of the 64 patients who were diagnosed with presumed ectopic pregnancies based on negative pathologic evidence and hCG levels that failed to demonstrate the requisite 15% postsampling decline, 59 patients (92.2%) received methotrexate. Four patients were treated successfully with repeat dosing of methotrexate; another 4 patients required laparoscopy after methotrexate for treatment of suspected ruptured ectopic pregnancies. Five patients in the ectopic pregnancy group underwent primary laparoscopy rather than treatment with methotrexate, because of patient preference, an enlarging adnexal mass, increasing pain, or complex pelvic free fluid on imaging concerning for ruptured ectopic pregnancy (Figure 2).
      Compared with the presumed ectopic pregnancy cohort, the failed IUP cohort required significantly fewer days from the time of Karman aspiration to a negative serum hCG level. On average, the failed IUP group had a negative hCG level 12.6 days after Karman aspiration, compared with 26.3 days in the presumed ectopic pregnancy group (β difference between groups, 13.16; 95% CI, 9.27–17.1; Figure 3). There was no difference identified in the time from Karman aspiration until the start of the next IVF cycle, although not all women in the study pursued further treatment.
      Figure thumbnail gr3
      Figure 3No. of days from Karman aspiration to negative serum beta-human chorionic gonadotropin
      The no. of days from Karman aspiration to negative serum beta-human chorionic gonadotropin among patients with an intrauterine pregnancy compared with patients with ectopic pregnancy is shown. Patients with failed intrauterine pregnancy had statistically significant shorter interval to resolution of pregnancy, with 12.6 days to negative beta-human chorionic gonadotropin compared with 26.3 days in the ectopic pregnancy group. The asterisk indicates the linear regression estimate adjusted for beta-human chorionic gonadotropin at time of Karman aspiration.
      hCG, beta-human chorionic gonadotropin; IUP, intrauterine pregnancy.
      Insogna et al. Karman biopsy to diagnose pregnancy location. Am J Obstet Gynecol 2017.
      There were no complications associated with the Karman aspiration protocol. There were no known uterine perforations, bleeding complications, infections, or injuries associated with the procedure. One patient required repeat Karman aspiration because of insufficient tissue obtained for analysis. No patients went on to require dilation for retained products of conception or other indications. All women tolerated the procedure well in the office, some with a paracervical block of 1% lidocaine according to clinician preference; none required intravenous sedation.

      Comments

      This study affirms the efficacy and safety of an endometrial aspiration protocol with the use of Karman cannula for diagnosing PUL. Nearly one-half of women with PUL (42%), who may have been treated empirically with methotrexate at other institutions were spared exposure to a potent chemotherapeutic agent with known potential side-effects and obtained faster resolution of their failed pregnancies.
      In the cohort of failed IUPs, patients (54.4%) did not have intrauterine villi identified; all patients, however, had a decline in serum hCG level of at least 15% after Karman aspiration. The Karman aspiration may disrupt an abnormal IUP in the uterus but fail to aspirate the few villi that leads to a decline in serum hCG level in the absence of confirmatory pathology results. The reliability of serum hCG level decline alone attests to the utility of the Karman aspiration for pregnancies of unknown location, regardless of clinical access to rapid histologic analysis.
      Of note, there was no lower limit of serum hCG level at the time of Karman cannula aspiration at which this protocol was not efficacious. Although a low serum hCG level logically might be thought to correspond to low trophoblastic tissue burden, which suggests that blind endometrial sampling might miss these few villi, even if they are intrauterine, the Karman aspiration successfully spared methotrexate exposure in women with serum hCG levels as low as 13 IU/L.
      No demographic or IVF cycle characteristics were predictive of ectopic pregnancy. Commonly referenced risk factors for ectopic pregnancy, which include tubal factory infertility, history of ectopic pregnancy, and adnexal mass on ultrasound scanning, statistically were not associated significantly with the diagnosis of presumed ectopic pregnancy after endometrial aspiration for PUL in this study. This finding may be the result of the small sample size or reflective of the very early stage of diagnosis attained in this study, as compared with studies that assessed ectopic pregnancies visualized by ultrasound scans or presenting with rupture. This finding suggests that all patients with PUL and abnormal hCG trends should be treated according to this protocol, because clinical characteristics cannot be used reliably to predict the final diagnosis of pregnancy location.
      Karman aspiration procedures are minimally invasive and well-tolerated in the office, with or without local anesthetic. This represents a more cost-effective approach than dilation, which requires the use of intravenous sedation or general anesthesia, in addition to the hospital resources that are necessary for a full surgical booking in an operating room.
      • Ailawadi M.
      • Lorch S.A.
      • Barnhart K.T.
      • et al.
      Cost-effectiveness of presumptively medically treating women at risk for ectopic pregnancy compared with first performing a dilatation and curettage.
      Previous retrospective and prospective data have demonstrated manual vacuum aspirations to be as well tolerated as evacuations in an operating room, without incurring any additional risk.
      • Dean G.
      • Cardenas L.
      • Darney P.
      • Goldberg A.
      Acceptability of manual versus electric aspiration for first trimester abortion: a randomized trial.
      • Goldberg A.B.
      • Dean G.
      • Kang M.-S.
      • Youssof S.
      • Darney P.D.
      Manual versus electric vacuum aspiration for early first-trimester abortion: a controlled study of complication rates.
      The lack of any complications in the study, with the exception of a single repeated procedure for insufficient tissue, highlights the safety of this procedure.
      Future studies are needed to compare the efficacy of Karman cannulas and endometrial biopsy pipelles for the diagnosis of pregnancy location. Previous studies have compared pipelles only with traditional dilation and have not evaluated serum hCG levels after pipelle biopsy.
      The time saved by the use of the Karman aspiration protocol is of particular relevance for women who are eager to conceive again. Women in the failed IUP cohort achieved resolution of their PUL an average of 2 weeks earlier than those in the ectopic pregnancy group, in addition to avoiding the 3 month waiting period after methotrexate before attempting conception. This finding has important clinical consequences in expediting subsequent pregnancy attempts, which is relevant to women both conceiving spontaneously or with ARTs. The physical and psychologic benefits gained from an expedited resolution are important for women with an undesired pregnancy as well, which expands the relevance of these findings to the general gynecology population. Furthermore, patients who were diagnosed with failed IUP received a definitive diagnosis within 24 hours of their procedure and the reassurance that they will most likely not require any further treatment. This is in contrast to patients with ectopic pregnancy, who are subjected to at least 7 anxiety-provoking days of waiting to determine whether their methotrexate treatment was successful, with the ongoing associated concerns for ectopic pregnancy rupture.
      It is critical that hCG levels are followed weekly until undetectable in patients with PUL that is treated with this protocol. Three additional presumed ectopic pregnancies were detected in the surveillance period after Karman aspiration; all 3 patients had sufficient postsampling hCG level declines with subsequent serum hCG level plateau and/or rise. All 3 were successfully treated with single-dose methotrexate. These presumed ectopic pregnancies would have been missed in the absence of diligent surveillance.
      Despite the doubling of sample size compared with the initial work published by Brady et al
      • Brady P.
      • Imudia A.N.
      • Awonuga A.O.
      • Wright D.L.
      • Styer A.K.
      • Toth T.L.
      Pregnancies of unknown location after in vitro fertilization: minimally invasive management with Karman cannula aspiration.
      in 2014, the relatively small sample size may be 1 limitation of this study. Limited statistical power may preclude us from reporting a statistically significant relationship that may be found in subsequent larger studies. Pathologists were not blinded to the clinical scenario, which may lead to potential bias during tissue analysis. The use of a database with many contributors introduces the possibility of human error with data capture, although all data for the 135 patients who underwent Karman aspiration were confirmed directly in the clinical electronic medical record. Furthermore, the study is retrospective, and its results should be confirmed in additional prospective patient populations. Prospective data that would evaluate and would confirm the efficacy of an outpatient endometrial sampling protocol would be instrumental in the implementation of a change in clinical practice.
      This study has many strengths that include the precise pregnancy dating by the use of data from an IVF population, which allows for reliable diagnosis of PULs at gestational ages for which ultrasound findings of normally progressing IUPs would otherwise be expected. In addition, demographic and detailed reproductive and ART treatment data routinely were documented for these patients, who are closely followed in very early pregnancy as standard of care. The IVF population is thereby an ideal population to pilot this protocol, which likely has applications to the general population of pregnancies of unknown location conceived spontaneously. A recent large review of data from the National ART Surveillance System over 10 years reported an ectopic pregnancy rate after ART (1.7%) similar to the ectopic pregnancy risk that is associated with spontaneous conceptions, which suggests the generalizability of these findings to all women with PUL, particularly because infertility diagnoses and IVF cycle parameters were not associated with ectopic pregnancy diagnosis among patients in this study.
      • Perkins K.M.
      • Boulet S.L.
      • Kissin D.M.
      • Jamieson D.J.
      Risk of ectopic pregnancy associated with assisted reproductive technology in the United States, 2001-2011.
      This study supports the utility and safety of an outpatient endometrial aspiration protocol, which spares a large proportion of women with PULs exposure to methotrexate. Furthermore, this study contributes the findings that nearly one-half of the women additionally benefited from the expedited resolution of their failed pregnancies. The results of this study advocate for the future prospective investigation of a Karman aspiration protocol for women with PULs as an alternative to presumptive methotrexate.

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