Low thrombin generation in postmenopausal women using estetrol

OBJECTIVE: Estetrol (E4) represents a novel estrogen of interest to relieve vasomotor symptoms. E4 activates the nuclear estrogen receptor α (ERα) but antagonizes the estradiol ERα-dependent membrane-initiated steroid signaling pathway. The distinct pharmacological properties of E4 could explain its low impact on hemostasis. This study aimed to assess the effect of E4 on coagulation in postmenopausal women, using the thrombin generation assay (TGA). METHODS: = 31) was administered daily for 12 weeks. Thrombograms and TGA parameters were extracted for each subject at baseline and after 12 weeks of treatment. RESULTS: = 168), as well as for TGA parameters. CONCLUSIONS: The intake of E4 15 mg for 12 weeks led to significant but not clinically relevant changes compared to baseline as the mean values (±95% CI of the mean) remained within reference ranges, demonstrating a neutral profile of this estrogen on hemostasis.