Children born to women taking antidepressants in early pregnancy have a small but important increased risk of septal heart defects (a defect in the wall dividing the right side of the heart from the left side), concludes research published on bmj.com today.

Depression affects up to 20% of pregnant women and the use of selective serotonin reuptake inhibitors (SSRIs) during pregnancy is common and increasing. However, medical treatment must balance the health of the mother with potential adverse effects to the developing baby.

Until 2005, most studies of SSRIs found no link with major malformations, but recent studies have indicated an increased prevalence of congenital heart defects. This led to a warning by the US Food and Drug Administration in 2005 about the use of the drug paroxetine during pregnancy.

So a team of researchers investigated the association between SSRIs taken in the first trimester of pregnancy and major malformations in over 400,000 children born in Denmark between 1996 and 2003.

Potential confounding factors, including maternal age and smoking, were taken into account.

However, an increased risk of septal heart malformations was found for children of women who used the drugs sertraline and citalopram, but not fluoxetine.

Exposure to more than one type of SSRI was associated with a four-fold increase in septal heart defects, suggesting that simultaneous use of different SSRIs or a change in type of SSRI during early pregnancy may be problematic, say the authors.

Putting these figures into context, the authors show that the absolute differences in heart defects were low. For example, septal heart defects occurred in 2,315 (0.5%) of unexposed children, 12 (0.9%) of SSRI exposed children, and 4 (2.1%) of children exposed to more than one type of SSRI.

The number needed to harm was 246 for women using one type of SSRI in early pregnancy. In other words, one child for every 246 children exposed was likely to suffer a septal heart defect. The corresponding number needed to harm for children of women using more than one type of SSRI was 62.

Future studies, with much larger sample sizes, are needed to further investigate potential associations with more severe malformations, conclude the authors.

These results suggest that the absolute risk for individual pregnant women is very low, says Professor Christina Chambers from the University of California San Diego, USA, in an accompanying editorial. She urges both doctors and patients to carefully weigh-up the small risks associated with SSRIs against those linked with undertreatment or no treatment.

Link to paper
Link to editorial

Source
British Medical Journal