Alterations in platelet function during the ovarian cycle

Abstract

Steroid hormones may profoundly influence hemostasis; for example, as discussed for hormone replacement therapy, pregnancy and, being less obvious, for the ovarian cycle. We investigated primary hemostasis parameters using a platelet function analyzer (PFA-100^TM) during the follicular and luteal phases in 18 healthy young women without oral contraceptives. During the follicular phase, the mean closure time (CT) was 164.7 ± 56.7 s, and it decreased to 130.2 ± 30.6 s in collagen/epinephrine cartridges in the luteal phase (P = 0.0095). No significant difference could be found for CT values in collagen/adenosine diphosphate cartridges during the follicular phase as compared with the luteal phase (97.2 ± 24.2 s versus 89.6 ± 18.4 s, P = 0.174). Negative correlations between the CT values in collagen/epinephrine cartridges and von Willebrand factor from both phases of the cycle were found (follicular phase:r = −0.53; luteal phase:r = −0.54). Fibrinogen and fibrinogen degradation products were significantly increased in the luteal phase (2.49 ± 0.62 g/l versus 2.05 ± 0.59 g/l and 0.12 ± 014 versus 0.04 ± 0.04, P = 0.02 for both parameters) as compared with the follicular phase. No significant differences could be detected for plasminogen, plasmin–antiplasmin complex, prothrombin fragment 1 + 2 and D-dimer between the groups. This study indicates that platelet function is periodically altered during the ovarian cycle due to the influence of progesterone and estrogen on von Willebrand factor concentrations.