The kinetics of serum hCG and progesterone in response to oral and vaginal administration of misoprostol during medical termination of early pregnancy

Abstract

BACKGROUND: Misoprostol is widely used in combination with mifepristone for medical termination of pregnancy. We studied the endocrine parameters of trophoblast function during medical termination of early pregnancy using mifepristone in combination with oral or vaginal misoprostol. The effect of prolonged misoprostol administration was also examined. METHODS: Thirty-four women, requesting termination of pregnancy and with ≤63 days of amenorrhoea, received 200 mg of mifepristone on day 0, followed by either oral (n = 13) or vaginal (n = 21) administration of 0.8 mg of misoprostol on day 2. In 23 cases misoprostol administration was continued orally for an additional 7 days. Serum samples, collected up to 14 days following the beginning of the treatment, were analysed for hCG, progesterone and mifepristone. RESULTS: hCG and progesterone concentrations continued to increase until day 2. Following misoprostol, hCG and progesterone levels declined by 70.5 ± 8.8% and 61.3 ± 16.3% (mean ± SD) respectively, in 24 h. The percentage decline in hCG correlated inversely (P < 0.05) with the time taken to abort. The peak level of mifepristone measured on day 2 did not correlate with the decline in serum hCG or progesterone. The kinetics of hCG, progesterone and mifepristone were similar in the different treatment groups. CONCLUSIONS: The route and duration of misoprostol administration have no effect on the kinetics of serum hCG or progesterone during medical termination of early pregnancy.