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Obstetrics and Gynecology

Training Level

Resident PGY 3


Henry Ford Hospital


Introduction: To determine the prevalence of pregnancy of unknown location (PUL) in patients treated with Methotrexate (MTX) for nonsurgical diagnosis of ectopic pregnancy (EP). To determine the b-HCG treatment outcomes. Methods: Retrospective cohort study of patients who received MTX for treatment of EP over a 10-year period in an urban-based healthcare system. Wilcox test was used for statistical analysis. Results: A total of 150 pregnancies were identified as treated with MTX over a 10-year period. Pregnancies were classified based on reviews of ultrasound as pregnancy of unknown location (PUL), ectopic pregnancy (EP), or Intrauterine pregnancy (IUP). 47 were classified as PUL, 101 EP, 2 IUP. Approximately 1/3 of patients treated with MTX were PULs. The average baseline b-HCG was 2960MIU/ML and the average b-HCG at treatment was 4188MIU/ML for the entire cohort. Resolution of b-HCG levels with one dose of MTX differed between pregnancy types with PULs prescribed MTX at a lower b-HCG level on day of treatment (56% vs 27% at b-HCG of less than 1000MIU/ML) compared to EP. Additionally, 61% of the entire cohort were treated with 2 data points or less. 38% of PUL were treated with 1 to 2 b-HCG values and 82% PUL were treated at b-HCG <2000MIU/ML. Of the two IUPs, b-HCG level at treatment was 6267MIU/ML and 13353MIU/ML. Conclusion: There may be an underappreciated risk of inadvertent administration of Methotrexate to patients with early IUP. A minimum of three b-HCG assays over seven days in the diagnostic algorithm for EP would decrease treatment of PUL.

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Pregnancy of unknown location in a cohort of patients treated with methotrexate