Immediate postabortal contraception with a microdose combined preparation: Suppression of pituitary and ovarian function and elimination of HCG

Abstract

The effect of an oral contraceptive on the pituitary and ovarian function as well as on the elimination of HCG was studied in women volunteers who had had a first-trimester abortion. The contraceptive regimen was a combined preparation containing 30 micrograms of ethinylestradiol and 150 micrograms of d-norgestrel. The treatment was started on the day of abortion. Plasma concentrations of LH, FSH, HCG, estradiol and progesterone were measured by radioimmunoassay. The contraception was well tolerated and no objective side-effects were found. There were no ovulations during the 32-day observation period following the abortion, as indicated by the suppression of LH and FSH, and low plasma levels of progesterone. Plasma FSH concentrations were the best indicators of pituitary suppression during the treatment. However, individual variations in the degree of suppression were found. In each case, the FSH concentrations rose to follicular phase levels during the treatment-free week, indicating the recovery of pituitary function. Plasma estradiol concentrations remained at the low, prefollicular level throughout the observation period, except in one subject during the treatment-free week. Plasma progesterone concentrations were low except for a transient elevation between days 7 to 12 after the abortion when there were high levels of HCG. The treatment did not affect the elimination of HCG; an estimate of 36.7 days for the complete elimination was calculated from the results obtained with the specific RIA for the beta subunit of HCG.