Maternal alcohol drinking pattern during pregnancy and the risk for an offspring with an isolated congenital heart defect and in particular a ventricular septal defect or an atrial septal defect.

Background: This cohort study examines the possible association between maternal alcohol intake, including binge drinking, during pregnancy, and the subsequent risk of having a child with an isolated congenital heart defect and, more specifically, with the isolated form of ventricular septal defect (VSD) or of an atrial septal defect (ASD).

Methods: Participants were 80,346 pregnant women who were enrolled into the Danish National Birth Cohort in 1996-2002 and gave birth to a live-born singleton without any chromosome anomalies. Twice during pregnancy these women were asked about their intake of alcohol. Few (if any) women with an excessive/abusive intake of alcohol were enrolled into the Danish National Birth Cohort.

Results: Through linkage with the National Hospital Discharge Registry, we identified 477 infants with a diagnosis of isolated congenital heart defect registered at any time during their first 3½-years of life; they included 198 infants with a VSD and 145 with an ASD. Neither the number of episodes of binge drinking nor binge drinking during three different developmental periods was associated with VSD or ASD. Women drinking ½-1½, 2, and 3+ drinks of alcohol per week had adjusted prevalence ratios of delivering an infant with a VSD of 1.22 (95% CI = 0.90-1.66); 1.38 (95% CI = 0.83-2.28); and 1.10 (95% CI = 0.54-2.23), respectively. The test for trend was 0.29.

Conclusions: Prenatal exposure to low-to-moderate levels of alcohol on a weekly basis or occasional binge drinking during the early part of pregnancy was not statistical significantly associated with the prevalence of isolated VSD and ASD in offspring.