Differential Effects of Oral and Transdermal Estrogen/Progesterone Regimens on Sensitivity to Activated Protein C Among Postmeno

Emmanuel Oger, Martine Alhenc-Gelas, Karine Lacut, Marie-Thérèse Blouch, Nathalie Roudaut, Véronique Kerlan, Michel Collet, Jean-François Abgrall, Martine Aiach, Pierre-Yves Scarabin, Dominique Mottier for the SARAH Investigators

Objective— Activated protein C (APC) resistance not related to the factor V Leiden mutation is a risk factor for venous thrombosis. Oral estrogen replacement therapy (ERT) has been reported to induce APC resistance. Little is known about the effect of transdermal estrogen.

Conclusions— Our data show that oral, unlike transdermal, estrogen induces APC resistance and activates blood coagulation. These results emphasize the importance of the route of estrogen administration.