Evaluation of pretreatment and early treatment changes in serum β-hCG with methotrexate.

Background: Serum beta-human chorionic gonadotropin (β-hCG) is an important biomarker for the detection of ectopic pregnancies (EPs). The β-hCG levels between days 1 and 4 after methotrexate (MTX) treatment as an indicator of the success of the MTX in EP have been the focus of research.

Objectives: To determine whether the change in the β-hCG levels at day 1 and 4 and pretreatment at 48-hour increments can predict early treatment failure of single-dose MTX in EP.

Material And Methods: This was a retrospective study of 1120 EPs treated with a single dose of MTX. Treatment failure was defined as an obligation to proceed to surgery or the need for additional doses of MTX.

Results: A total 722 out of 1120 EPs had an increase in β-hCG on day 4 after MTX treatment. The logistic regression analysis indicated that 3 dependents were significantly associated with treatment failure: 1) a pretreatment 48-hour increase in β-hCG (odds ratio (OR): 1.249, 95% confidence interval (95% CI): 1.008-2.049, p < 0.001); 2) a change in β-hCG between day 1 and 4 (OR: 1.384, 95% CI: 1.097-2.198, p < 0.001); and 3) a history of EP (OR: 1.208, 95% CI: 1.041- 2.011, p < 0.001). The optimal cutoff point for the prediction of treatment failure was an increase of more than 19% in the 48 h before the treatment, and an increase of more than 36% between day 1 and day 4 in β-hCG concentrations. Patients with an increase in β-hCG levels of less than 36% on day 4 experienced MTX treatment failure in 4.2% (n = 25), compared to 74.5% (n = 88) of the patients with an increase above 36%.

Conclusions: A serum β-hCG increase of more than 36% on day 4 after the administration of MTX alongside a more than 19% increase in β-hCG concentration 48 h before the MTX treatment may predict the early failure of medical treatment for an EP.