New study shows an increased risk of birth defects while taking antidepressants during pregnancy—but take it with a grain of salt

Warning: If you’re taking antidepressants for anxiety or depression and you’re pregnant or planning a pregnancy, this story may cause panic—that is, unless you read it to the end.

Generally speaking, the chances of having a baby with a major birth defect are between three and five percent. But a new study published in the BMJ Open suggests that the risk may be from five to eight percent among women who take the antidepressant citalopram (Celexa) during their first trimester.

Concerning? Sure. But it’s important to take a step back and put the study’s findings in context with other research that has been done in the field. For the study, Anick Bérard, a professor of epidemiology in the faculty of pharmacy at the University of Montreal and a researcher at CHU Sainte-Justine children’s hospital, and her colleagues dug through data on 289,688 pregnancies that occurred in Quebec between 1998 and 2009. Using health and prescription records, the investigators identified 18,487 women who were depressed before becoming pregnant, 3,640 of whom had taken antidepressants during pregnancy. The investigators didn’t have information on smoking rates, alcohol use and folic acid intake—all of which influence the risk of birth defects—but these habits tend to be present in women with depression or anxiety. “In an effort to separate out the effects of the drugs, we didn’t look at the overall population of pregnant women but only those who were anxious and depressed,” says Bérard.

Among mothers who weren’t exposed to antidepressants during their first trimester, the rate of congenital malformations was 11.1 percent, which is in line with the provincial rate of 10 percent (the rate is higher in Quebec because many residents descend from a small number of early settlers). When women who had taken antidepressants were divided up by medication class, the rates in three of the four groups were slightly higher: 12 percent for SSRIs (the most popular class, which includes paroxetine/Paxil and sertraline/Zoloft); 12.3 percent for SNRIs (such as venlafaxine/Effexor); 13.4 percent for tricyclics (such as amitriptyline/Elavil); and 10.9 percent for “others” (such as bupropion/Wellbutrin). When the researchers looked at individual medications, they found that taking citalopram was linked to a 36 percent increase in the likelihood of major birth defects, compared to not being exposed to antidepressants. Among average-risk women, that translates into a jump from five percent to eight percent. “That may seem small, but if you have a child with a birth defect, the consequences are devastating,” says Bérard.

What do all of these numbers really mean? First of all, you can’t draw definite conclusions from a single study—you have to look at an accumulation of research. (Drug effects during pregnancy are tricky to study because randomized trials—the gold standard for evidence—are rarely conducted on pregnant women.) It’s also still possible that the rates of smoking, prenatal vitamin use and drinking—all of which are associated risks—varied between the two groups, despite the theory that looking only at women with anxiety or depression would adjust for these factors. A US study, published in the New England Journal of Medicine in 2014, which studied a much larger group of people, used a different method of balancing the groups and took the severity of depression into account, found no major increase in the risk of major heart defects in babies of women who had taken antidepressants compared to those whose mothers hadn’t taken these drugs.

And what about the 0.9 percent gap between babies of women who weren’t exposed to antidepressants and those whose mothers took SSRIs? According to Simone Vigod, a psychiatrist and lead of the Reproductive Life Stages Program at Women’s College Hospital in Toronto who read the study but wasn’t involved in the research, “The margin of error suggests that the rates aren’t even different.” As for the spike in risk among women who took citalopram, the more you analyze the numbers, the greater the odds that results will differ due to chance alone, explains Vigod. “While more research is needed, we’re never going to be able to give a 100 percent answer,” she says, “because nobody can guarantee a good or bad pregnancy outcome.”

What does all this mean for a living, breathing woman who’s trying to decide whether or not to take antidepressants during pregnancy? Bérard argues that, because these drugs have been found to be only marginally effective in mild to moderate depression, it’s worth considering other evidence-based treatments, such as psychotherapy and exercise, in these cases. “Depression is serious, and you should treat it or consider treating it,” she says. “But for the majority of pregnant women who are mildly to moderately depressed, the benefits of these drugs will not likely exceed the risks.”

When deliberating over whether the potential benefits of antidepressant treatment outweigh the risks for you personally, you also need to take your mental health history into account and discuss your situation with your healthcare provider. Birth defects aside, depression during pregnancy may also increase the odds of other problems, such as preterm birth and low birth weight, and untreated severe depression during pregnancy can be dangerous to both mom and baby due to the risks of self-harm and severe postpartum depression.

In her clinic, which sees about 1,000 patients each year, Vigod walks women through the potential pros and cons. “None of the women I see makes this decision lightly,” she says. “If you had an anxiety problem 10 years ago and went on antidepressants but never had any reason to stop and you think you might like to get pregnant, then someone like me is going to say “Yes, I think you should probably come off the drug and see how you do.” (She generally recommends tapering off these drugs gradually under medical supervision because quitting abruptly can cause very unpleasant side effects, such as agitation and anxiety spikes.) However, if you were hospitalized three times for severe depression and tried four medications before finding one that worked, Vigod may advocate continuing treatment because your risk of relapse will be pretty high if you go off the mediation, she says.

To help guide more women through these difficult decisions, Vigod and her colleagues have created a web-based tool that they are currently testing in an online study, with results expected in May. (If you’re pregnant and grappling with the question of whether to start, stop or continue taking antidepressants and you’re interested in participating, click here. They will be recruiting participants until the end of February.) “It’s amazing how many women don’t feel they have support for this decision,” she says.

Read more: Antidepressants during pregnancy: Support, not stigma I took antidepressants while pregnant and it saved my life Recognizing the signs of postpartum depression