Clinical aspects of three new progestogens: desogestrel, gestodene, and norgestimate.

Three new 19-nortestosterone progestogens, which are chemically related to levonorgestrel, are now clinically available in combination oral contraceptives in Europe. Desogestrel and norgestimate must be transformed to metabolites for all or part of their biologic activity; gestodene is active in its original form. Compared with present low-dose monophasic and triphasic levonorgestrel formulations, the new combinations appear to be equivalent in efficacy and type and frequency of side effects. Cycle control may be slightly improved with the gestodene preparation and somewhat poorer with the desogestrel regimen. As with the present triphasics, most changes reported in coagulation indexes for the new combinations remained within normal limits, as did changes in carbohydrate and lipid metabolism. There is no present evidence that either the norgestimate or aesogestrel formulation provides a clinical improvement over the levonorgestrel triphasic. In the gestodene combination, the progestogen's increased biologic activity allows further reduction of total steroid dose.