A COMPARATIVE STUDY OF LOW DOSAGE ORAL CONTRACEPTIVES.

3 low dosage oral progestagens norethynodrel 2.5 mg norethindrone 2 mg and ethynodiol diacetate 1 mg all with mestranol .1 mg have been used in a contraceptive trial for the past 2 years covering 7602 treatment cycles or 684 woman years of experience in Puerto Rico. All 3 have been acceptable effective and reversible. Norethynodrel has shown more breakthrough bleeding (BTB) and more nausea in the early cycles with a tendency to diminish with continued usage. Norethindrone has shown a significantly greater tendency toward weight gain. Ethynodiol diacetate has shown more silent menstruation or amenorrhea. Chloasma has been responsible for 2% of the terminations. In the annual physical examinations the incidence of chloasma was noted to have increased 3 times over pretreatment examination levels with norethindrone and ethynodiol diacetate and was twice as frequent with norethynodrel. There has been no reduction in fertility but rather a slight enhancement following termination of medication. Approximately 84% of former users at risk of pregnancy were pregnant within 6 months of discontinuance of medication. The 78 babies born to these women have been normal.