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

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.