UC Davis

Anticoagulation poses unique challenges for women of reproductive age. Clinicians prescribing anticoagulants must counsel patients on issues ranging from menstruation and the possibility of developing a hemorrhagic ovarian cyst to teratogenic risks and safety with breastfeeding. Abnormal uterine bleeding affects up to 70% of young women who are treated with anticoagulation. As such, thoughtful clinical guidance is required to avoid having young women who are troubled by their menses, dose reduce, or prematurely discontinue their anticoagulation, leaving them at increased risk of recurrent thrombosis. Informed by a review of the medical literature, we present current recommendations for assisting patients requiring anticoagulation with menstrual management, prevention of hemorrhagic ovarian cysts, and avoiding unintended pregnancy. The subdermal implant may be considered a first-line option for those requiring anticoagulation, given its superior contraceptive effectiveness and ability to reliably reduce risk of hemorrhagic ovarian cysts. All progestin-only formulations-such as the subdermal implant, intrauterine device, injection, or pills-are generally preferred over combined hormonal pills, patch, or ring. Tranexamic acid, and in rare cases endometrial ablation, may also be useful in managing menorrhagia and dysmenorrhea. During pregnancy, enoxaparin remains the preferred anticoagulant and warfarin is contraindicated. Breastfeeding women may use warfarin, but direct oral anticoagulants are not recommended given their limited safety data. This practical guide for clinicians is designed to inform discussions of risks and benefits of anticoagulation therapy for women of reproductive age.