Pharmacodynamics of combined estrogen-progestin oral contraceptives: 2. effects on hemostasis.

INTRODUCTION: The pharmacodynamic effects of various combined oral estrogen-progestin combinations (COC) are examined for their components alone or in the various combined formulations. Special emphasis is given to products containing natural estrogens. Areas covered: Recent information on the effect of androgens, estrogens, progestins, as well as various COC combinations on the coagulation cascade will be reviewed aiming at providing an updated picture. The present article reviews hemostatic changes occurring during use of classic and modern combinations of estrogens (ethinyl estradiol, estradiol, estradiol valerate and estetrol) and new progestins (desogestrel, gestodene, dienogest, drospirenone, nomegestrol acetate), compared to classic compounds, such as levonorgestrel. Both pro- and anti-coagulatory effects of COC in healthy women are detailed and possible links with incidence of thromboembolic events are discussed. Expert commentary: Overall, the picture is reassuring: the use of natural estrogens and of new generation progestins has reduced pro-coagulatory changes in healthy subjects, although the observed differences in the risk of venous thromboembolism between second and third generation progestins is still incompletely understood. At the same time, there still is a need for large comparative and surveillance studies before firm conclusions can be drawn. At any rate, available evidence indicates that hemostatic effects of the newer COC, especially those utilizing natural estrogens, are minimal and often remain with the normal range.