Key result
First-trimester exposure to DOACs was not associated with an increased risk of major birth defects compared to LMWH (2.9% vs 4.3%; OR 0.74; 95% CI 0.33-1.67).
Why the study?
Direct oral anticoagulants are increasingly prescribed to women of childbearing age, raising concerns about reproductive safety after inadvertent first-trimester exposure.
Does first-trimester exposure to DOACs increase the risk of major birth defects or pregnancy loss compared to LMWH in pregnant women?
Cohort (n=1,041)
Yes
Does first-trimester exposure to DOACs increase the risk of major birth defects or pregnancy loss compared to LMWH in pregnant women?
First-trimester DOAC exposure does not appear to increase the risk of major birth defects or pregnancy loss compared to LMWH, providing reassurance for cases of inadvertent maternal exposure.
BACKGROUND: Direct oral anticoagulants (DOACs) are increasingly prescribed to women of childbearing age, making inadvertent first-trimester exposure more likely. OBJECTIVES: We prospectively evaluated the risks of major birth defects and pregnancy loss following first-trimester DOAC exposure. METHODS: We conducted a multicenter, observational prospective cohort study comparing pregnancy outcomes in women exposed to a DOAC during the first trimester of pregnancy and a reference group of women exposed to a low molecular weight heparin (LMWH) during the first trimester, between 2008 and 2024. RESULTS: A total of 343 DOAC-exposed and 698 LMWH-exposed pregnancies were included. DOAC exposure was not associated with an increased risk of major birth defects (DOAC n = 8/279, 2.9%; LMWH n = 25/586, 4.3%; adjusted odds ratio, 0.74; 95% CI, 0.33-1.67). In the cumulative incidence analysis (340 DOAC and 688 LMWH), the rates of live birth, pregnancy loss, and pregnancy termination were 73%, 13%, and 14% in the DOAC group and 75%, 20%, and 5% in the LMWH reference group. Cox proportional hazards cause-specific models indicated no increased risks for pregnancy loss after DOAC exposure, but a higher hazard of pregnancy termination. CONCLUSIONS: First-trimester DOAC exposure was not associated with a substantially increased risk of major birth defects or pregnancy loss, and the observed defects did not suggest a teratogenic pattern, consistent with reported findings in the existing literature. These results offer further reassurance for counseling in case of inadvertent exposure. Larger studies are still warranted to validate these findings due to a limited sample size and window of exposure.
No takes yet. Share an insight, caveat, or question.
Dao et al. (2026) conducted a cohort in First-trimester pregnancy (n=1,041). First-trimester direct oral anticoagulants (DOACs) vs. First-trimester low molecular weight heparin (LMWH) was evaluated on Major birth defects (adjusted OR 0.74, 95% CI 0.33-1.67). First-trimester exposure to DOACs was not associated with an increased risk of major birth defects compared to LMWH (2.9% vs 4.3%; OR 0.74; 95% CI 0.33-1.67).
Synapse has enriched 5 closely related papers on similar clinical questions. Consider them for comparative context: