Antidepressants Safer Than Believed During Pregnancy

June 28, 2007 — -- Pregnant women who might benefit from antidepressants can take heart in a new study that suggests popular depression medications are safer for their babies than once believed.The research, however, falls short of declaring the drugs completely safe, as they may still be associated with a minutely higher risk of certain rare birth defects.

The impact of the research could be far reaching, as each year as many as 400,000 pregnant women in the United States suffer from major depression.

In many patients with depression, doctors prescribe drugs called selective serotonin reuptake inhibitors, or SSRIs, a category that includes Prozac, Zoloft, Paxil and Celexa. Previously, doctors had worried that these drugs could cause birth defects in unborn children.But depression itself also carries certain risks during pregnancy. Left untreated, it can lead to complications such as preterm delivery, a difficult birth, low birth weight and other detrimental effects to the newborn.

Having the drugs as an available option could therefore help some women who might otherwise have difficulty dealing with their condition.

"Basically, our study is somewhat reassuring. We now know that SSRIs do not lead to an increased in risk for birth defects in general," said Jennita Reefhuis, an epidemiologist at the National Center on Birth Defects and Developmental Disabilities and a lead author of the study, which appears in the current issue of the New England Journal of Medicine.

Dr. Zachary Stowe, director of the Women's Mental Health Program at the Emory University School of Medicine, agreed. "Overall, it's a very reassuring data set," he said. "The reality in these birth defect studies is that in the women exposed to antidepressants, their overall rate of birth defects wasn't any different than the general population."

Depression Drug Fears

Major concerns over depression drugs taken during pregnancy surfaced in the fall of 2005, when GlaxoSmithKline, the maker of the SSRI antidepressant Paxil, found that pregnant women who were on the drug had an increased chance of having babies with holes in their hearts.

In their studies, women on the medication had a 1.5 to 2 percent risk of having a child with a heart defect, as compared with a 1 percent risk in mothers not taking the drug.

"When we saw the reports on the association between SSRIs and birth defects, we knew that we had to look in our data to see if we found similar associations," said Reefhuis.

She and her collaborators at the Centers for Disease Control and Prevention work on the National Birth Defects Prevention Study, which examines different factors that could contribute to birth defects, including taking medications during pregnancy.

The team looked at 9,622 mothers whose children had birth defects and compared them with 4,092 mothers whose children were normal when born.

They looked at 18 different categories of defects, including eight subcategories of heart problems, and found no significant increase in most of these conditions for mothers who were on SSRIs.

Still Not Completely Risk Free?

However, the researchers did find a connection between using these antidepressants and a two- to three-fold increase in three specific birth defects -- an incomplete formation of the brain which results in death, an abnormal development of the skull and a type of hernia in which internal organs stick out through the navel.

But Reefhuis said these risks are so small to begin with that modest increases would be nearly insignificant."For the three defects we discussed, they're pretty rare -- so even quadrupling the risk still leads to a less than 1 percent risk that the mother would have a child with one of these birth defects," she said.

The absolute risk of getting these diseases was so small that further investigations would be necessary to confirm that the links did not show up due to chance alone. Another study conducted by researchers at Boston University and Harvard University, also published in New England Journal of Medicine this week, looked at the same three birth defects, among others, and found no overall connection between SSRIs and these maladies.

"It's a fairly reassuring article," said Dr. Jennifer Niebyl, head of obstetrics and gynecology at the University of Iowa. "The numbers are sufficiently small that you can't say that this is cause and effect."

Women's mental health expert Stowe agrees that this is good news, but says it is not the end of the story."Reassuring studies, but it's only one piece of the picture," said Stowe. "Just because the medicine doesn't cause birth defects, that's one side of the coin; what about any long-term effects?"

For this reason, he said, more research is needed before the drugs can be declared completely harmless to unborn babies.

"So far, most of the studies with antidepressants have been pretty good, but there haven't been that many done," Stowe said. "I'm glad they're not finding birth defects, but I don't want studies like this to greenlight wholesale prescribing of these medicines to anyone."

That is a message Reefhuis and her colleagues hope women and their doctors will take to heart. "I think it's really important that women talk to their health care provider to discuss their individual situation," she said, adding that she hopes women and their physicians will work together "to come up with the best possible course of action for that specific woman."