Blood Loss in Women of Childbearing Potential Taking Oral Anticoagulants for Venous Thromboembolism (The BLEED Study).

Oral anticoagulants (OAC) may exacerbate menstrual bleeding in women of childbearing age; however, the existing literature on this issue has several limitations. This study investigates abnormal uterine bleeding (AUB) in women of childbearing age taking oral anticoagulants-Vitamin K antagonists (VKA) or Direct Oral Anticoagulants (DOAC)-for venous thromboembolism through a retrospective analysis of prospectively collected data. Uterine bleeding was assessed using the Pictorial Blood Assessment Chart (PBAC) and hemoglobin (Hb) values during anticoagulation compared to prior therapy. The number of unplanned medical visits for bleeding complications was also calculated. From June 2014 to November 2023, 110 women were recruited (median age, 36 years). PBAC scores correlated with Hb values at baseline and during therapy (ANOVA, p<0.01), with a significant difference in Hb values before and during anticoagulant therapy (Δ Hb) among groups (ANOVA, p=0.034). Seventeen women (15.4%) reported fibroids, experiencing a greater reduction in Hb values during anticoagulant administration than women without fibroids (Δ 0.3, IQR -0.8, 2.9 vs -0.5, IQR -1.2, 0.3; p=0.012). Women with fibroids required more frequent unplanned medical consultations for bleeding (mean visits 5 vs 4 respectively; Poisson regression, p<0.05). Among women with fibroids, those taking apixaban showed smaller Hb changes than those on other oral anticoagulants (ANOVA, p=0.047). This difference persisted even after adjusting for potential confounders (MANOVA, p=0.004). Women of childbearing potential taking OAC frequently experience changes in Hb values and PBAC scores during treatment, with fibroids playing a significant role.