The natural oestrogenic hormone oestradiol as a new component of combined oral contraceptives.

The synthetice estrogenic compound ethinyl estradiol depresses the activator content of vessel walls. Biologically equivalent doses of the natural estrogenic hormone estradoil do not have this effect. Estradiol also impairs liver function less than synthetic estrogens. Estradiol is a natural estrogen obtained from soy beans. The new Micronizing technique favors absorption. The effects of a pill designated Netagen containing 4 mg of micronized estradiol and 3 mg of norethisterone were studied over a 1-year period. The pill was taken for 21 consectutive days and withdrawn for 7 days of consecutive cycles. Subjects were 25 normal women. No pregnancies or throbmoembolic incidents occurred in 204 cycles. Spotting was noted by 7 patients. 2 developed amenorrhea but 1 of them had previously had amenorrhea. Emotional disturbances were noted by 2. The menstrual flow was unchanged in 12 and decreased in 13. No increase in blood pressure was recorded. Weight increased in 4 and decreased in 2. 11 of the 25 women stopped taking the pill after 3-6 months; the other 14 continued. Results of this pilot study suggest that this preparation may be an improvement as a new combined oral contraceptive as it seems less likely to cause thromboembolic complications.