Antidepressant use in pregnancy and severe cardiac malformations: Danish register-based study

Studies restricted to live births may underestimate severe teratogenic effects. We address the limitation by including data from both prenatal and postnatal diagnoses of cardiac malformations.

Register-based study.

Denmark.

364 012 singleton pregnancies from 2007 to 2014.

We used data from five nationwide registries. Exposure to antidepressants was measured using redeemed prescriptions.

Pregnancies with cardiac malformations that end in miscarriage, termination, stillbirth, postnatal death or cardiac surgery <1 year of birth were classified as severe cardiac malformations (SCM). Propensity scores with adjusted prevalence ratios (PRs) were calculated.

SCM were reported in 972 of 364 012 pregnancies overall and in 16 of 4105 exposed. For venlafaxine, the PR for SCM was 2.13 (95% confidence interval [CI] 0.89-5.13), 1.73 (95% CI 1.08-2.77) for other cardiac malformations, and there was a cluster of hypoplastic left heart syndromes (HLHS) (crude PR 17.4 [95% CI 6.41-47.2]), none of which ended in a live birth. For HLHS, the absolute risk increase was 4.4/1000 and the number needed to harm was 225. For selective serotonin reuptake inhibitors, the PRs were 1.09 (95% CI 0.52-2.30) and 1.38 (95% CI 1.00-1.92) for SCM and other cardiac malformations, respectively.

Pregnancy exposure to venlafaxine is associated with an increased risk of severe cardiac malformations but with a low absolute risk. Potential mechanisms include direct effects or confounding by indication. Venlafaxine exposure is a marker for risk pregnancies for which fetal echocardiography may be considered.

Exposure to venlafaxine is associated with an increased risk of cardiac malformations but with a low absolute risk.