Clinical experience with the recently developed progestogens.

The third generation of combination estrogen/progestogen oral contraceptives (OCs) first became available in the early 1980s. The gonanes (e.g., norgestimate, desogestrel, and gestodene) are alternatives to the long-standing progestogens, norethindrone and norgestrel/levonorgestrel. While the newer compounds are related to levonorgestrel, their biochemical structure differs. All, however, are strongly progestogenic with respect to ovulation inhibition and are very selective in their affinity for endometrial progesterone receptors. At present, experience with the third-generation combined OCs is relatively limited, and extensive comparative data have yet to be accrued. Nevertheless, these ultra-low-dose compounds appear to be as efficacious as the traditional OCs, while their cycle control may be slightly superior. In addition, the incidence of minor side effects, such as nausea, weight gain, and mastalgia, compares favorably with that of the earlier OCs. In combination with estrogen, these new progestogens have revealed a neutral or possibly beneficial effect on lipid/lipoprotein metabolism. Thus, the newer progestogens do not appear to have adverse effects on the cardiovascular system and offer a range of noncontraceptive health benefits.