Morbid obesity and outcome of ectopic pregnancy following capped single-dose regimen methotrexate.

Purpose: Evaluate whether morbid obesity influenced resolution, number of doses or ultimately surgical management of tubal ectopic pregnancy (TEP) when treated with single-dose regimen methotrexate (SDR-MTX) capped at 100 mg.

Methods: Retrospective cohort study of patients with a diagnosis of TEP who underwent MTX treatment from 2000 to 2013. Patients were excluded if initial β-hCG <1000 mIU/mL, did not have β-hCG follow-up or were not treated with SDR-MTX. Per protocol, dose was administered at 50 mg/m with a capped maximum of 100 mg. Patients were divided based on their BMI (<40 and ≥40 kg/m). Demographic variables, β-hCG before treatment, maximum diameter of ectopic size, embryonic heart tones, decrease of β-hCG, need for additional MTX doses and surgery despite treatment were recorded and compared among the groups.

Results: 151 women were included in the study, 89.4% (135/151) non-morbidly obese and 10.6% (16/151) morbidly obese. No differences in age distribution, ethnicity, pre-treatment presence of embryonic heart tones, maximum diameter of ectopic size ≥35 mm and β-hCG ≥5000 mIU/ml were found. Following treatment, the proportion of patients with at least an 80% decrease in their β-hCG levels or need for surgery were similar, however, morbidly obese patients were significantly more likely [11/134 vs. 5/16, OR 5.1 (1.5-17.3, p = 0.015)] to require an additional MTX dose.

Conclusion: Among patients with TEP, morbidly obese patients were five times more likely to require an additional dose compared to non-morbidly obese when SDR-MTX capped at 100 mg was used for medical management.