Aim: We aimed to determine the predictivity of decrease in serum hCG value on day 4 of single-dose methotrexate (MTX) regimen for the need for surgery in patients with intact tubal ectopic pregnancy (TEP).

Methods: We evaluated 41 patients diagnosed with intact TEP and treated with single-dose intramuscular injection of MTX treatment according to body surface area (50 mg/m2). Serum hCG values on days 0, 4, and 7 were retrieved to determine patterns of hCG change. Clinical data of patients with treatment success or failure were analyzed.

Results: Of 41 patients, 31 was successfully treated with MTX administration, and in the rest (n=10), surgery was required because of intraabdominal hemorrhage. On days 0, 4, and 7, the median serum hCG values in patients with treatment failure were significantly higher compared to treatment success (p<0.05). In the patients with treatment failure, the median hCG values on day 7 was significantly lower than that on day 4 (p<0.05).

Conclusion: During the follow-up of patients with intact TEP who administered single-dose MTX regimen, decrease of serum HCG value on day 4, in addition to low HCG value and endometrial thickness on day 0, is valuable to predict treatment failure.

Keywords: tubal ectopic pregnancy, ectopic pregnancy, hCG, methotrexate, treatment failure, tubal surgery