Serum levels of FSH, LH, estradiol-17 beta and progesterone following the administration of a combined oral contraceptive containing 20 micrograms ethinylestradiol

Abstract

An oral contraceptive containing 20 micrograms of ethinylestradiol and 250 micrograms of levonorgestrel was given to 5 normally menstruating women for two consecutive cycles. Peripheral serum levels of FSH, LH, estradiol-17 beta and progesterone were determined during the treatment period and during two control cycles, one immediately before, and one immediately after treatment. In all 5 women studied there were no LH peaks and no luteal phase levels of progesterone during the treatment cycles indicating complete inhibition of ovulation. 4 of the 5 women showed no biphasic estradiol pattern. Posttreatment control cycles showed reestablished ovulatory pattern in 4 of the 5 subjects.

PIP: This study investigated the effect of a combination pill containing only 20 mcg of ethinyl estradiol (EE) on the hypothalamus-pituitary-ovarian axis. 5 healthy women (aged 17-24 years) with cycle lengths 28+ or -2 days were administered SH D 382 A (Schering Corp.), an oral contraceptive (OC) consisting of 20 mcg of EE and 250 mcg of levonorgestrel. The following endocrine parameters were measured: follicle stimulating hormone, luteinizing hormone, estradiol, progesterone, and estrone. The results of hormone assays are presented graphically. The 1st control cycle showed normal ovulatory patterns in 4/5 women; during treatment all patients demonstrated hormone profiles indicating complete inhibition of ovulation. Posttreatment control cycles showed ovulatory patterns in 4/5 women. The ratio of OC components studied here was 1:12.5 compared with normal 1:5 ratios, yet this markedly modified ratio did not seem to significantly alter the hormonal pattern during treatment compared to 1:5 ratio OCs (i.e., there were no luteinizing hormone peaks and no luteal phase levels of progesterone). It is hoped that reduced EE levels will mitigate against increased incidences of thromboembolic disease.