[Rationalizing progestin-only contraception (except IUS with levonorgestrel)]

Using pure progestin contraception has four main objectives; all pure progestins on the market do not satisfy these four main objectives: (i) not to give artificial estrogens like ethinyl estradiol or any kind of estrogens at high doses. This is necessary when there is an estrogeno-dependent pathology; (ii) to diminish endogen estrogen circulating levels by using anti-gonadotrope progestins; (iii) not to induce dangerous proteins synthesis by a too important estrogenic hepatic impact due to an effect, known as hepatic passage. This is required in case of metabolic pathologies or more largely, in case of important vascular risk factors or also in case of an estrogen-dependent hepatopathy; to diminish hormonal fluctuations for women who have problems due to varying endogen hormones. Knowing each product's pharmacology enables to choose the product best adapted to each clinical situation. When choosing, one has to take into account the contraceptive efficiency, as well as the fact that those products are often given over long periods of time to women with particular pathologies.