OC 62.1 - Oral anticoagulants and bleeding in reproductive age women: fibroids matter.

Background: Up to 70% of anticoagulated menstruating women experience Heavy Menstrual Bleeding (HMB). Limited studies suggest that Direct Oral Anticoagulants (DOACs) show a more favorable bleeding profile compared to Vitamin K Antagonists (VKAs).

Aims: To investigate whether and to what extent different OACs affect menstrual bleeding.

Methods: We identified medical records of women between 18–50 years with venous thromboemboembolism (VTE) (9/2016 to 10/ 2023). Type and initiation age of Oral Anticoagulants (OAC), general demographics were recorded. Exclusion criteria: menopause prior to OAC initiation, OAC use within 6 months of a pregnancy or 3 months of lactation. We assessed menstrual blood loss using blood count and Pictorial Blood Assessment Chart (PBAC) at enrollment and during therapy. Descriptive statistics and multiple ANOVA (MANOVA) were used to evaluate associations between OAC type, DOAC class, age, fibroids and difference in hemoglobin levels during vs before OAC.

Results: 110 women met inclusion criteria (Table 1), all took therapeutic doses. No difference in prescription of type of OAC was observed by age, type of VTE, with the exception of women with CVT who were significantly more prescribed with VKA than DOAC ( 25.8% vs 8.3%, p: 0.02). We calculated Delta hemoglobin (Hb)- i.e. difference between Hb during minus Hb before therapy –that was not significantly higher in those taking VKAs vs DOAC. Women taking apixaban showed a significantly difference in DeltaHb even after correction for confounders (age, fibroids, comorbidities, duration of anticoagulation, iron therapy p: 0.004). DeltaHb was significantly different among those with fibroids compared to those without (median -0.3,IQR -3, 2.9 vs -0.5, IQR -1.2,-0.3 p: 0.012). Among women with fibroids, those taking apixaban showed a safer DeltaHb profile compared to those taking other OAC (p: 0.047) (Tables 2,3).

Conclusion(s): OAC prescribers in fertile women should consider sex-specific characteristics. Apixaban shows the safest profile even for women with fibroids.