The return to ovulation following early abortion: a comparison between vacuum aspiration and prostaglandin

Abstract

The return to ovulation following early abortion (less than or equal to 56 days amenorrhea) has been assessed after both vacuum aspiration under general anesthesia (N = 14) and menstrual induction with 16,16 dimethyltrans-delta 2PGE1 methyl ester in pessary form (N = 18). The urinary excretion of hCG, total estrogen and pregnanediol was similar in each group. There was an initial rapid decline in hCG excretion (t1/2 48 h), reaching 10% of the pre-treatment value after 6 days. Twenty-nine (91%) women showed a luteal phase rise in pregnanediol excretion, with ovulation occurring on day 29 (16-37) and 24 (16-32) in the vacuum aspiration and prostaglandin groups, respectively (median (range) NS). The wide range in the return of ovarian activity was related to the variation in decline of progesterone secretion (as reflected by excretion of pregnanediol) by the corpus luteum. Asynchrony between the ovarian and menstrual cycles resulting from a delay to ovulation presents a major constraint to the use of early pregnancy interruption as a routine method of fertility control.

PIP: Analysis of the endocrine profile after early abortion, whether by vacuum aspiration or menstrual induction, indicates that the levels of human chorionic gonadotropin (hCG), estrogen, and progesterone decline slowly over several days before reaching prepregnancy levels. The return to ovulation following early abortion (under 56 days of amenorrhea) was assessed in 2 groups: 14 women who underwent vacuum aspiration under general anesthesia and 18 women whose abortion was medically induced with 16,16 dimethyl-trans-delta 2-prostaglandin (PG) El methyl ester in pessary form. The pattern of excretion of hCG, total estrogen, and pregnanediol following abortion was similar in both groups. hCG excretion reached 10% of the pretreatment value after 6 days in each study group. After a rapid fall in total estrogen secretion, there was a gradual increase in the follicular phase, followed by a more rapid rise prior to, and maintained after, ovulation itself. 29 (91%) women showed a luteal phase rise in pregnanediol excretion compatible with ovulation. The median length of the luteal phase was 13 days in the vacuum aspiration group and 11 days in the group treated with PGE1. There was a correlation between the day on which the urinary pregnanediol to creatinine ratio 1st dropped to 20-30 mgmol/mmol and the day of the return of ovulation. Ovulation was delayed by 29 days on average in the vacuum aspiration group and by 24 days in the prostaglandin group. Asynchrony between the menstrual and ovarian cycles represents a major constraint to the use of menstrual induction as a routine means of postcoital contraception.