One of the most common classes of mood disorder drugs, selective serotonin-reuptake inhibitors, or SSRIs, are frequently prescribed for depression and anxiety symptoms, but little is known about their impact on the baby during pregnancy.
"Discuss your use of antidepressants during pregnancy with your doctor."
Hana El Marroun, Ph.D., of Sophia Children's Hospital and Erasmus Medical Center in the Netherlands, and colleagues studied 7,696 pregnant women to see how depression and the use of SSRIs affected both the mothers and the babies.
In the study, 91 percent of the women had low or no symptoms of depression, and a little over 7 percent had depression symptoms but did not take SSRIs. A total of 99 women, or 1.3 percent, took SSRIs.
El Marroun's team found that both untreated depression and the use of SSRIs were linked to similar growth issues in the babies, but at different levels of severity.
Babies born to women with depressive symptoms that went untreated tended to have a lower overall body growth, including their heads, during pregnancy, whereas babies born to mothers taking SSRIs had reduced growth in the head but not in the body.
The reduction in fetal head growth was greater in the babies of mothers taking SSRIs compared to those with untreated depression.
Mothers taking SSRIs were also twice as likely to give birth early, but the untreated depressive mothers tended to give birth a day later, on average, compared to the mothers without depression.
Separate research has found associations between fetal head size and brain weight or behavioral or psychiatric problems, but the authors write that this study could not - and should not - be used to show any link between SSRI use and future developmental issues.
"More long-term drug safety studies are needed before evidence-based recommendations can be derived," the authors conclude.
The study was published online March 5 in the Archives of General Psychiatry.