Oral anticoagulant therapy tied to risk of abnormal uterine bleeding

Oral anticoagulant users, particularly young women, have an increased likelihood of abnormal uterine bleeding, according to a nested matched case–control study.

Researchers used the MarketScan Research Databases and identified women initiating oral anticoagulants (warfarin, apixaban, rivaroxaban, dabigatran, and edoxaban) for deep venous thrombosis, pulmonary embolism, or atrial fibrillation or flutter. These women were matched to nonusers of anticoagulants.

Abnormal uterine bleeding within 1 year was the primary outcome. Secondary outcomes included the risk of hospitalizations, emergency department visits, and outpatient encounters related to abnormal uterine bleeding.

The analysis included 276,911 anticoagulant users and 1,384,555 matched nonuser controls. Abnormal uterine bleeding was documented in more anticoagulant users vs nonusers (6.1 percent vs 3 percent; adjusted odds ratio [AOR], 1.81, 95 percent confidence interval [CI], 1.69–1.93).

Moreover, anticoagulant users had greater odds of abnormal uterine bleeding-related hospitalization (0.8 percent vs 0.01 percent; AOR, 62.32, 95 percent CI, 30.94–125.53), emergency department visits (0.9 percent vs 0.2 percent; AOR, 5.78, 95 percent CI, 4.02–8.31), and outpatient encounters (4.6 percent vs 2.8 percent; AOR, 1.42, 95 percent CI, 1.32–1.52).

Notably, the odds of abnormal uterine bleeding associated with anticoagulant use vs nonuse were greater among young women (<50 years of age: 19.7 percent vs 9.2 percent, AOR, 1.96, 95 percent CI, 1.79–2.14) than older women (≥50 years: 3.8 percent vs 2 percent; AOR, 1.63, 95 percent CI, 1.50–1.78).

Among oral anticoagulant agents, rivaroxaban was associated with the highest risk of abnormal uterine bleeding.

The present data highlight the need for proactive counselling, routine menstrual history assessment, and collaborative management strategies, particularly between gynaecologists and haematologists, at the time of anticoagulant initiation.