Effects of Certain 19-Nor Steroids on the Normal Human Menstrual Cycle

Preliminary trials of 17alpha-ethinyl-19-nortestosterone (norethynodrel) 17alpha-ethinyl-5(10)-estraeneolone (norethisterone) and 17alpha-ethyl-19-nortestosterone in 50 infertile women are described. Patients were 22-39 years old (mean 29) ovulating and menstruating regularly but infertile for 1.5-6 years. They took 5-50 mg of one of the progestagens from Cycle Days 5-25 for a total of 112 cycles. Cycle length endometrial biopsies basal temperature vaginal smears and pregnanediol excretion were monitored. In only 2 cycles with norethisterone were any 2 of these criteria suggestive of ovulation but pregnediol remained .1 mg/day (an ovulatory range). In most respects norethynodrel and norethisterone had identical effects; fo r example endometria showed stimulated stromal but retarded glandular development and exhibited menstruallike bleeding between cycles. Ethyl-19-nortestosterone however permitted only breakthrough bleeding in 8 of 16 women. All 3 compounds inhibited ovulation in doses above 10 mg daily. 7 (15%) women conceived within 5 months after the trial including 5 who had been infertile for 3-6 years.