Change in serum β-human chorionic gonadotropin after abortion with methotrexate and misoprostol, ,

OBJECTIVE: The purpose of this study was to determine the normal β-human chorionic gonadotropin change within 24 hours after a medical abortion. Because a medical abortion creates a “miscarriage,” these data can represent the serum β-human chorionic gonadotropin changes that would occur with a complete spontaneous abortion. Knowledge of normal β-human chorionic gonadotropin changes after a spontaneous abortion may help to differentiate within a 24-hour period a complete from an incomplete spontaneous abortion or an ectopic pregnancy. STUDY DESIGN: Data from recent trials that used methotrexate and misoprostol for abortion at ≤56 daysʹ gestation were reviewed. Patients from each of four trials were included in this analysis if (1) they received both methotrexate intramuscularly and misoprostol vaginally and (2) they had serum β-human chorionic gonadotropin levels drawn on both the day of misoprostol administration and the next day. RESULTS: The change in serum β-human chorionic gonadotropin was evaluated in 86 patients. Subjects who had a complete abortion after receiving methotrexate and a single dose of misoprostol had a decline in serum β-human chorionic gonadotropin of 66% ± 8%. All other subjects had a decline of 25% ± 19% (p = 0.0001). CONCLUSIONS: An aborting pregnancy, if the abortion has occurred, should have a β-human chorionic gonadotropin decrease of at least 48% within approximately 24 hours. This decline, however, does not guarantee that the abortion is complete. A patient with a serum β-human chorionic gonadotropin level that has not declined by a minimum of approximately 50% over 24 hours is unlikely to have a complete abortion. (AM J OBSTET GYNECOL 1996;174:776-8.)