[Contraception using normal dose progestins].

Contraceptive use of normal dosed progestins continues to be useful for many women who cannot use other contraceptive methods, but appropriate use depends on perfect knowledge of their modes of action, advantages, disadvantages, dosages, and duration of action. Each progestin has its own indications, and contraindications, and not all progestins have contraceptive properties. Most progestins used for contraception are derived from 19 nor-testosterone. Structural modifications of progesterone and testosterone have produced synthetic progestins resistent to hepatic degradation and bioavailable through the oral route. 2 main groups of progestins may be distinguished: androgenic progestins, including the estrone derivatives ethynodiol diacetate and lynestrenol, which have stong antigonadotropic activity and a braking effect on endogenous estrogen secretion, and "pure" progestins derived from 17 OH progesterone, or norpregnanes, such as chlormadinone and promegestone, which have strong luteomimetic activity, no androgenic activity, and weak antiandrogenic activity. Norsteroids administered at normal doses for 21 days/month or in some cases 17 days have a Pearl index of around 1%. This type of contraception requires counting days and taking 1 or 2 pills, and should only be used for women with certain types of problems or hormonal imbalances requiring treatment. Indications may include some cases of uterine polyps, endometrial mucus hyperplasia, uterine fibromas, endometriosis, mastodynies, benign mastopathies, existence of several risk factors for breast cancer, age over 40 years, premenopausal luteal insufficiency, and smoking. Secondary effects, especially metabolic disturbances, may occur and vary according to the formulation, route of administration, and duration of treatment. The 19 nortestosterone progestins commonly used because of their antigonadotropic and antiestrogenic activity have measurable effects on lipid metabolism, apparently in relation to apoproteins A and B, and on glucose metabolism. Some have an effect on the renin substrate, but their role in provoking arterial hypertension appears to be modest. Androgenic effects such as seborrhea and acne may be produced at some dose levels. Medroxyprogesterone acetate, derived from 17 OH progesterone, causes significant metabolic changes including androgenic and hypertensive effects, undesirable effects on glucoregulation, and coagulation effects.