The new progestins

Abstract

Despite the large number of studies on the new progestins there is a great need for well-designed, prospective, comparative clinical trials. Such studies are needed to adequately compare the commonly used older formulations with the newer ones as well as to compare the many different new formulations among themselves. Until these studies become available, conclusions must be based on the available data. Formulations containing desogestrel, gestodene, and norgestimate have some similarities but also some clinical advantages over the older low-dose formulations. The newer compounds have similar efficacy and cycle control to the older low-dose monophasic formulations. From a biochemical point of view, the new progestins seem to have a better selectivity index than their predecessors. They also display some metabolic benefits with regard to protective lipid fractions, elevations of SHBG, and decreases in free testosterone. The long-term benefits of the favorable lipid changes remain to be elucidated. The favorable androgenic profile can be taken advantage of in clinical situations in which androgenic side effects become a concern. Coagulation effects and effects on carbohydrate metabolism appear to be similar to those of other low-dose formulations and of little clinical significance. Norplant and DMPA are both progestin-only, long-acting, reversible contraceptives that are useful in situations in which compliance may be difficult. Both contraceptives can be used in women who must avoid estrogen and in the immediate postpartum period. They can also be used in lactating women. Whereas the return of fertility in Norplant users is rather quick, DMPA users must be counseled that amenorrhea and anovulation can be prolonged after its discontinuation. Norplant has no significant adverse metabolic impact on users, whereas DMPA may cause unfavorable changes in lipids and carbohydrates.