Methotrexate failure in women with prior ectopic: our experience with the two-dose methotrexate protocol

Abstract

OBJECTIVE: Methotrexate (MTX) therapy of ectopic pregnancy (EP) is safe and effective in appropriate cases. Previous data suggest that women with previous EP have an increased failure rate when treated with a single-dose MTX protocol. Our objective was to investigate if previous EP remained a risk factor for MTX failure in our population where most women receive a two-dose MTX protocol. DESIGN: Retrospective cohort MATERIALS AND METHODS: Data were abstracted from all cases of confirmed EP between 1999 and 2007 regarding presentation, evaluation, treatment, and history of EP. Parametric and non-parametric methods were used to compare variables; multivariable logistic regression was used to assess the effect of prior EP on MTX failure. RESULTS: We identified 202 cases primarily treated with MTX; 17.3% had a history of EP, 83% received 2-dose MTX therapy. There was no difference between women with and without previous EP in bleeding, pain, or gestational age at presentation, or days from presentation to MTX. The overall risk of MTX failure was 16.3%. The unadjusted OR for MTX failure in women with prior EP vs no EP was 2.06 (95%CI 0.75,5.24; p=0.10). In adjusted models the association between MTX failure and prior EP differed depending on the ultrasound (u/s) at presentation (interaction p =0.04). When the u/s was suspicious for EP (free fluid, mass) no increased risk of MTX failure with prior EP was observed (OR=0.44, 95%CI: 0.07, 2.77; p=0.38). However, in those with a non-diagnostic u/s, prior EP increased the odds of MTX failure by 5.65 (95%CI: 1.16, 27.48; p=0.03). HCG level at treatment also carried an increased odds of MTX failure (p=0.002). CONCLUSIONS: Prior EP is a risk factor for MTX failure in women in our population who present with a non-diagnostic u/s. It is important to recognize these women as higher risk, and both monitor and counsel these patients accordingly.