Taking selective serotonin reuptake inhibitors (SSRIs) during early pregnancy does not significantly increase the likelihood of most birth defects, including heart malformations.
That is the conclusion of two studies, one conducted by the CDC and the other by epidemiologists at Boston University. Previous research had linked SSRIs and congenital heart defects, resulting in FDA-ordered warning labels on the drugs.
The CDC scientists examined data from a nationwide study of 9,622 children with major birth defects and 4,092 normal children. The mothers had taken SSRIs during the month before they became pregnant or during the first trimester.
Looking for associations between four SSRIs—sertraline (Zoloft), paroxetine (Paxil), fluoxetine (Prozac, Sarafem, Symbyax), and citalopram (Celexa)—and 26 types of defects, the CDC team found only three, and all were rare. Of the 214 infants with anencephaly, only nine had been exposed to SSRIs; of 432 infants with craniosynostosis, 24 had been exposed; and of the 181 with omphalocele, 11 had been exposed (N Engl J Med. 2007;356:2684-2692).
“Overall, our results are reassuring,” said Jennita Reefhuis, PhD. “Both the mother and baby benefit when a pregnant woman with a serious illness is able to stay on some sort of treatment.”
In Boston, researchers studied 9,849 infants with birth defects and 5,860 normal infants, all of whose mothers also took SSRIs during their first trimesters. Unlike the CDC team, which looked at SSRIs collectively, these researchers analyzed the correlation between specific drugs and specific defects (N Engl J Med. 2007;356:2675-2683).
A number of pairings were statistically significant: sertraline with omphalocele; sertraline with septal defects; and paroxetine with right ventricular outflow-tract obstruction defects. However, “the absolute risks are very small,” the investigators reported. For example, right ventricular outflow-tract obstruction occurs in about 55 of every 100,000 births. “Even if a specific SSRI increased rates by a factor of four, the risk of having an affected child would still be only 0.2%,” they wrote.