Antidepressants Linked to Birth Defect

Sept. 24, 2009 -- New research adds to the evidence that babies born to women who take antidepressants during pregnancy have a small increased risk for a specific heart defect.

The Danish study also shows that the risk is greatest when moms-to-be take more than one selective serotonin reuptake inhibitor (SSRI) antidepressant or switch SSRIs early in pregnancy.

SSRIs such as Prozac, Paxil, Zoloft, Celexa and Lexapro are the most widely prescribed drugs for depression; millions of women take them during pregnancy.

The new study shows the overall risk for congenital heart problems associated with SSRI to be quite low.

But babies born to women who had filled prescriptions for more than one SSRI had a fourfold increase in septal heart defects -- a malformation of the wall that divides the left and right sides of the heart.

Unclear if All SSRIs Carry Risk

The finding will no doubt add to the confusion surrounding the safety of specific SSRIs during pregnancy.

In 2005, based on the research at the time, the FDA singled out the drug Paxil, warning that its use was associated with an increased risk for heart defect.

It has since become common practice for doctors to switch women taking Paxil to another SSRI when they become pregnant or are considering pregnancy.

But more recent studies suggest that women who take Paxil have no greater risk for delivering babies with the heart defect than women who take other antidepressants.

In the Danish study, use of Celexa and Zoloft early in pregnancy was associated with a small increased risk for the heart defect, but no association was seen in women who took Paxil or Prozac.

The study compared the incidence of birth defects among babies born to Danish women who did and did not take SSRIs during their first trimester. The study included more than 400,000 children born between 1996 and 2003.

Septal heart defects occurred in 0.5% of children born to mothers who did not take antidepressants and 0.9% of children born to mothers who did. SSRI use was not linked to any other major birth defect.

"The bottom line is the risk associated with SSRI use appears to be very small, and this has to be balanced against the very real risk associated with having untreated depression during pregnancy," study researcher Lars H. Pedersen of Aarhus University tells WebMD.

Larger Studies Needed

Pedersen says much larger studies are needed to determine whether any one SSRI is safer or less safe than any other during pregnancy.

In an editorial published with the study Friday in BMJ Online First, birth defects researcher Christina Chambers, PhD, agrees that larger studies are needed.

Chambers is an epidemiologist and associate professor at the University of California, San Diego School of Medicine.