Link Between Antidepressants and Birth Defect

September 29, 2009 by Lin Edwards

Fluoxetine (Prozac). Image: Wikimedia Commons

(PhysOrg.com) -- Researchers in Denmark have studied almost half a million Danish children and found a slightly higher rate of septal heart abnormalities in babies whose mothers took an SSRI antidepressant drug during early pregnancy, especially if they took more than one type.

The scientists, Lars Henning Pedersen and colleagues, from Aarhus University in Denmark, aimed to identify any relationship between taking selective serotonin reuptake inhibitors (SSRIs) during pregnancy and birth defects.

SSRIs are the drugs most often prescribed for women suffering from depression, and in the U.S. around 13% of pregnant women take these common antidepressant drugs, and there has been a concern for some time that the drugs might affect the developing fetus.

The research, published last week in the medical journal BMJ, was a population cohort study of 493,113 children born in Denmark between 1996 and 2003. It looked at the incidence of birth defects, including heart abnormalities, and prescription SSRIs taken by the women in the first trimester.

The study found the risks of taking SSRIs were generally low, and no association was found with birth defects except that the rate of septal heart defects was slightly elevated. Septal heart defects are abnormalities in the wall dividing the left and right ventricles in the heart.

The incidence of septal heart defects was 0.5% (2315 of 493,113) in unexposed babies, 0.9% (12 of 1370) in babies of mothers who took one SSRI, and 2.1% (4 of 193) in babies of mothers who took more than one type of SSRI. Sertraline (Zoloft) and citalopram (Celexa) were associated with a slightly higher incidence than fluoxetine (Prozac) and paroxetine (Paxil, Pexeva).

Research in the U.S. in 2005 found that Paxil taken during pregnancy was associated with a slightly greater risk or heart defects in the fetus, but later studies, including the Danish study, have not confirmed this.

Dr Pedersen said more research is needed to decide if any particular SSRI is safer than another, since the various studies have implicated different drugs. As Professor Chambers of the University of California in San Diego writes in an editorial accompanying the research paper, the risk of taking the antidepressants is extremely low and must be counterbalanced by the very real risks of leaving serious depression undertreated.

More information:

• Selective serotonin reuptake inhibitors in pregnancy and congenital malformations: population based cohort study, BMJ 2009;339:b3569, doi:10.1136/bmj.b35doi:10.1136/bmj.b3525#8226; Editorial: BMJ 2009;339:b3525, doi:10.1136/bmj.b3525

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