Ruptured ectopic pregnancies following methotrexate treatment: clinical course and predictors for improving patient counseling.

To determine the predictors for tubal rupture among women treated with methotrexate (MTX) for ectopic pregnancy. We performed a retrospective cohort analysis in a tertiary university-affiliated medical center. Medical records of 401 women who were diagnosed with ectopic pregnancy and were treated with MTX between January 2001 and June 2017 were reviewed. Forty-one women were diagnosed with ruptured ectopic pregnancy (study group) and 360 women with non-ruptured ectopic pregnancy (control group). Descriptive data and predictive variables for rupture ectopic pregnancy following MTX treatment were reviewed. Out of 122 women who failed MTX treatment, forty-one women had tubal rupture (33.6%). The median time interval from MTX treatment to tubal rupture was 6 days (1-25). β-hCG percentage change in the 48 h preceding MTX treatment and β-hCG level at day 0 were independent predictors for tubal rupture (odds ratio [OR] = 1.08, 95% confidence interval [CI] = 1.04-1.12, p < 0.001 for every percent change in β-hCG; OR = 1.001, 95% CI = 1.0003-1.002 for every unit change in β-hCG, respectively). In a decision tree analysis model, in women with β-hCG percentage increment >69% in the 48 h preceding methotrexate the probability for tubal rupture was 85%. Risk assessment for tubal rupture should be made before methotrexate treatment according to β-hCG dynamics and level. The absolute risk for tubal rupture in women with β-hCG increment<20% is low.