Feb. 23, 2010 — Babies born to women who take antidepressants during pregnancy may experience small delays in reaching certain developmental milestones, but it is not clear if these delays are clinically significant, a study shows.

Compared to children born to women who did not take antidepressants, children born to women who did sat up for the first time, on average, 16 days later and walked almost a month later.

The exposed children still reached these milestones within the range of what is considered normal development. But the findings suggest antidepressant use during pregnancy has some impact on the fetal brain, study researcher Lars Henning Pedersen, MD, PhD, of Denmark’s Aarhus University tells WebMD.

“We can’t say if this impact is clinically meaningful,” Pedersen says. “We really need longer follow-up of these children to say this with more certainty.”

Motor Delays Did Not Persist

Animal studies have linked early exposure to antidepressants to lasting behavioral changes, but previous studies in humans have failed to confirm this finding.

In the newly published study, Pedersen and colleagues examined data from close to 82,000 babies born in Denmark between 1996 and 2002.

A total of 415 were born to mothers who used antidepressants during pregnancy, 489 were born to mothers who reported depression but did not take medication, and 81,042 were born to mothers who did not report depression or antidepressant use.

Most of the treated women took selective serotonin reuptake inhibitors (SSRIs), such as Prozac, Zoloft, Celexa and Paxil.

Some took tricyclic antidepressants, a few took the serotonin norepinephrine reuptake inhibitor (SNRI) Effexor, and a few more took a combination of antidepressants.

The mothers provided information on a wide range of developmental milestones when their babies were around 6 months and 19 months old.

At age 6 months, babies born to mothers who took antidepressants in their second and third trimesters were twice as likely to be unable to sit up without support as babies born to women who didn’t take antidepressants.

The delay was significant only for exposed boys, who were three times as likely to need assistance sitting up at age 6 months as unexposed babies.

No difference in motor development was seen at age 19 months, but the antidepressant-exposed toddlers did exhibit shorter attention spans than the unexposed toddlers.

There was little difference between the antidepressant-exposed and unexposed babies in other milestones, including language, hearing, and social development.

The study appears in the March issue of Pediatrics.

In a separate study reported last fall, Pedersen and colleagues found that antidepressant use during pregnancy may be associated with a slight increase in risk for a rare heart malformation.

For both studies, the researchers used data from a Danish birth registry.

Second Opinion

Psychiatrist Kimberly A. Yonkers, MD, says studies like these are important, but they also have major limitations, especially in patients being treated for depression.

She says people who are depressed or who take antidepressants are more likely to engage in risky behaviors such as smoking, drinking, and using recreational drugs. They are also more likely to be on other prescription drugs.

Yonkers is a professor of psychiatry and obstetrics, gynecology, and reproductive medicine at Yale School of Medicine.

“Teasing out the effects of antidepressants in the presence of these other issues and the psychiatric condition in general is really difficult,” she says.

She points out that antidepressant use has been linked to early delivery, but so has untreated depression.

Yonkers was lead author of guidelines on antidepressant use during pregnancy published last fall by the American Psychiatric Association (APA) and the American College of Obstetrics and Gynecology (ACOG).

The guidelines recommend that:

• Pregnant women or those considering pregnancy should not be taken off antidepressants if they experience severe depression, psychotic episodes, have a diagnosis of bipolar disorder, have a history of suicide attempts, or are suicidal.
• Women with mild depression and those who have had few symptoms for six months or longer can consider gradually reducing their drug doses or stopping the drugs altogether under the close supervision of their prescribing doctor.
• Psychotherapy and other non-drug treatments may be an appropriate alternative to drugs during pregnancy for some, but not all, women with depression.

Yonkers says her patients often know when they can get by without antidepressants and when they need to stay on them during pregnancy.

“It would not be appropriate to tell a woman who relapses every time she goes off her drugs to stop taking them,” she says. “But a woman with mild chronic depression who tells me she hasn’t had an episode in years might not need them.”