CDC: Certain Antidepressants, But Not All, Taken During Pregnancy May Raise Birth Defect Risk

The debate over whether or not it's safe to take antidepressants during pregnancy is heated, with extreme emotions — and conflicting research studies — on both sides.

But a broad new analysis led by researchers at the U.S. Centers for Disease Control and Prevention came to a fairly measured conclusion when comparing pregnant women who took SSRIs — a class of antidepressants — to women who did not take those medications during pregnancy.

The analysis suggests that certain serious birth defects occur 2 to 3.5 times more frequently among babies born to mothers taking the antidepressants Prozac or Paxil early in pregnancy. But the researchers also conclude that for pregnant women taking other SSRIs, such as Zoloft, the data "provide some reassuring evidence" that earlier studies linking the drug with specific birth defects could not be replicated.

The analysis of 17,952 mothers of infants with birth defects and 9,857 mothers of infants without birth defects was published in The BMJ.

"What our paper really adds, is that we can now offer women more options," said Jennita Reefhuis, an epidemiologist with the CDC's National Center on Birth Defects and Developmental Disabilities and the study's lead author. Reefhuis said that since Zoloft (sertraline) was the most common SSRI taken among the women, "it was reassuring that we could not replicate the five earlier links with birth defects."

In an interview, Reefhuis said: "The main message is that depression and other mental health conditions can be very serious and many women need to take medication to manage their symptoms. So women who are pregnant, or thinking of becoming pregnant, shouldn't stop or start any antidepressants without speaking to a health care provider."

The issue, she added, isn't clear cut, but highly dependent on each individual woman and a very personal calculation of risks versus benefits. "We are trying to find the nuance here," Reefhuis said. "It is really important that women get treated during pregnancy. Their illness doesn't stop the moment they get pregnant. Women need options."

It's also important to retain perspective when evaluating risk, Reefhuis said, noting that in every pregnancy there is already a 3 percent risk of a birth defect.

Indeed, the study authors note that with regard to taking SSRIs during pregnancy, "the absolute risks for these birth defects are still low." They write: "If these associations are causal, the absolute risks in the children of women who are treated with paroxetine [Paxil] early in pregnancy would increase for anencephaly [a brain and skull formation problem] from 2 per 10,000 to 7 per 10,000, and for right ventricular outflow tract obstruction [a heart defect] from 10 per 10,000 to 24 per 10,000."

To help women better understand their options and the complexities of the topic, the CDC has launched a new initiative: Treating for Two: A National Strategy For Safer Medication Use During Pregnancy.


Here's more from the BMJ news release:

A team of researchers based in the USA and Canada combined results from independent published analyses with data from the US National Birth Defects Prevention Study (NBDPS) to provide a more robust estimate of the association between individual SSRIs and birth defects.

Their analysis included 17,952 mothers of infants with birth defects and 9,857 mothers of infants without birth defects, born between 1997 and 2009.

Use of the SSRI drugs citalopram (Celexa), escitalopram (Lexapro), fluoxetine (Prozac), paroxetine (Paxil), or sertraline (Zoloft) at least once in the period from one month before conception through the third month of pregnancy was recorded.

Women who reported taking antidepressants other than SSRIs or reporting pre-existing diabetes were excluded.

Sertraline was the most commonly used SSRI, but none of the five previously reported associations between sertraline and birth defects were confirmed. This is reassuring, say the authors, as about 40% of women reporting use of an SSRI in early pregnancy used sertraline.

For nine other previously reported associations between maternal SSRI use and birth defects in infants, findings were also consistent with no association.

However, two previously reported birth defects associated with fluoxetine treatment were observed - heart wall defects and irregular skull shape (craniosynostosis).

Five previously reported birth defects associated with paroxetine treatment were also seen. These included heart defects, problems with brain and skull formation (anencephaly), and abdominal wall defects.

These data provide reassuring evidence for some SSRIs, say the authors, but suggest that some birth defects occur more frequently among the infants of women treated with paroxetine or fluoxetine in early pregnancy.

“Although our analysis strongly supports the validity of the associations that were observed, the increase in the absolute risks, if the associations are causal, is small,” they stress....

“Continued scrutiny of the association between SSRIs and birth defects is warranted,” they say, “and additional studies of specific SSRI treatments during pregnancy are needed to enable women and their healthcare providers to make more informed decisions about treatment.”

“Meanwhile, the current analysis provides guidance to the safest treatment options during early pregnancy to minimize the risk of major birth defects, while providing adequate treatment of maternal depression,” they conclude.

Headshot of Rachel Zimmerman

Rachel Zimmerman Reporter
Rachel Zimmerman previously reported on health and the intersection of health and business for WBUR. She is working on a memoir about rebuilding her family after her husband’s suicide. 



More from WBUR

Listen Live