Evaluation of pituitary-ovarian axis suppression with three oral contraceptive regimens.

BACKGROUND

The study was conducted to evaluate follicular development and hormone patterns with three oral contraceptive (OC) regimens before, during and after the 7-day hormone-free interval (HFI) or 7-day ethinyl estradiol (EE)-supplemented interval.

STUDY

DESIGN

The study is a single-center, open-label, prospective, randomized trial to evaluate pituitary-ovarian suppression with three OC regimens containing identical hormones: 30 mcg of EE and 150 mcg of levonorgestrel (LNG).

METHODS

After a standard 21/7 OC baseline cycle, subjects were randomized to one of three treatment groups: (1) three 21/7-day cycles of 150 mcg LNG/30 mcg EE for 21 days followed by 7 days of placebo (n=10); (2) one 84/7-day cycle of 150 mcg LNG/30 mcg EE for 84 days followed by 7 days of placebo (n=12) and (3) one 84/7EE-day cycle of 150 mcg LNG/30 mcg EE for 84 days followed by 7 days of 10 mcg EE (n=11). Estradiol; follicle-stimulating hormone (FSH); luteinizing hormone and inhibin-B levels, ovarian follicles and daily symptom diaries were collected.

RESULTS

Compared to subjects receiving placebo during the 7-day HFI, those receiving EE demonstrated reductions (p<.05) in both FSH and estradiol. Number of developing follicles was less after the 7-day EE interval compared to that after 7-day HFI. Subjects on the 84/7 and 84/7EE regimens reported less (p=.03) daily menstrual flow than those on the 21/7-day regimen. A trend (p=.06) toward reduced headaches during the 7-day EE-supplemented interval was noted.

CONCLUSIONS

Supplementation of the standard 7-day HFI with 10 mcg EE after 84 days of an extended OC decreased FSH levels and decreased the number of developing follicles.