Purpose: To investigate the predictive factors for the requirement of additional doses of methotrexate in women with ectopic pregnancy treated with single-dose methotrexate regimen.
Methods: This retrospective cohort study was conducted on women treated with single-dose methotrexate regimen for ectopic pregnancy at a tertiary referral center. Control group included the patients who were treated only with a single dose of methotrexate (n = 131) and study group included the patients who need a second dose or third dose methotrexate (n = 76). The sonographic variables such as size of the ectopic mass, the endometrial thickness and biochemical variables were analyzed via Chi square and student t test. Logistic regression analysis used to determine independent predictors of the additional dose requirement.
Results: The size of the ectopic mass and the endometrial thickness were similar in both groups. However, all human chorionic gonadotropin values on day 1, 4 and 7 were significantly higher in study group than the control group (p = 0.0001). Logistic regression analysis revealed that the human chorionic gonadotropin changes between day 1 and 4 is a predictive factor for requirement of additional doses of methotrexate (area under curve: 0.763, p < 0.001) and the cutoff value for human chorionic gonadotropin change was calculated as 22%. The probability of the requirement for an additional dose of methotrexate is 6.45 times more in patients who had less than 22% reduction in human chorionic gonadotropin levels from day 1 to 4 compared to those who had >22% reduction from day 1 to 4.
Conclusion: Less than 22% reduction in human chorionic gonadotropin levels from day 1 to 4 can be used as a predictive factor for the requirement of an additional dose of methotrexate in single-dose regimen. This cutoff value can be used for patients to inform about the probable longer resolution time and refer to alternative treatment modalities such as two-dose, multiple-dose regimens or surgery.