That should reassure the 8% to 13% of women who take antidepressants while expecting. Concerns about the risks of the drugs, primarily selective serotonin reuptake inhibitors (SSRIs), on the developing fetus prompted the Food and Drug Administration in 2005 to add warnings about the risk of heart defects in babies born to moms taking antidepressants. While studies have shown up to a three-fold increase risk in some congenital heart abnormalities associated with antidepressants, doctors couldn’t be entirely sure the higher risk wasn’t due purely to chance. Now, the New England Journal of Medicine reports that may indeed be the case, thank to the work of Krista Huybrechts, in the division of pharmacoepidemiology at Brigham and Women’s Hospital and Harvard Medical School, and her colleagues.
In their analysis involving 949,504 pregnant women, 64,389 of whom used antidepressants during the first trimester, the rate of heart defects in newborns was similar between the groups. “Based on our study, there is no evidence to support a substantial increased risk of cardiac malformations overall,” she says.
She and her team specifically focused on adjusting for potential confounding factors that could explain the heart malformations, such as age, how many children the women had had, diabetes, hypertension and use of psychotropic medications. Even after accounting for these effects, they found no strong association between antidepressant use and heart defects.
While the findings should be reassuring for expectant mothers who take antidepressants, Huybrechts says that “heart defects are one factor in a whole range of potential risks” associated with the drugs. Some studies hint, for example, that the medications may contribute to hypertension in newborns, as well as other adverse health conditions. “The study provides quite solid evidence of the low risk in terms of cardiac malformations, but the treatment decision should consider the whole range of other potential adverse outcomes,” Huybrechts says. “[Decisions also need to consider] potential risk of not treating women who are severely depressed and required pharmacologic interventions. It’s one piece of the puzzle but definitely not the whole answer.”