Comparative investigation of oral contraceptives using randomized, prospective protocols

Abstract

Combined oral contraceptives, containing a synthetic estrogen and a synthetic progestogen, have been in worldwide use for more than a generation. While only two estrogens (ethinyl estradiol and mestranol) have been used in commercial formulations, at least 14 different progestogens have been tried¹. Large epidemiological surveys of oral contraceptive users have suggested that some of the adverse clinical associations of oral contraception are related to the daily estrogen dose, though others are related to the daily progestogen dose². In an attempt to produce safer and more acceptable preparations, manufacturers have introduced a range of low dose oral contraceptive formulations. Particular attention has been placed on the estrogen component and most of these new formulations contain a daily dose of 30 or 35 μg estrogen. Epidemiological evidence suggests that these low estrogen formulations have indeed reduced the incidence of some rare, but serious, side-effects of oral contraception^3,4. Recently a new progestogen (desogestrel, ORG 2969) has also been introduced and claimed to have a more favorable impact on laboratory indices of cardiovascular risk⁵. The present study was undertaken to compare the metabolic impact of several different oral contraceptive formulations on young, healthy, new oral contraceptive acceptors.