Women who take antidepressants during pregnancy may be more likely to have children with autism, a Canadian study suggests.
The overall risk is low – less than 1 percent of the nearly 150,000 babies in the study were diagnosed with autism by age six or seven.
But children of women who took antidepressants during the second and third trimesters of pregnancy were 87 percent more likely to develop autism than kids born to women who didn’t take the drugs, researchers report in JAMA Pediatrics.
“Depression is a serious and debilitating condition,” said lead study author Anick Berard of the University of Montreal. “This study is not advocating untreated depression. However, it is certainly advocating treatment of depression with something other than antidepressants during pregnancy.”
Some women, particularly if their symptoms are mild, may be able to manage depression during pregnancy with exercise or psychotherapy, Berard added.
The study doesn’t prove antidepressants cause autism. It also doesn’t explore the potential harms of untreated depression or assess whether remedies other than medication might be safer or more effective for women and their babies.
Left untreated, depression during pregnancy is associated with underweight babies who are more likely to wind up in neonatal intensive care. Pregnant women with uncontrolled depression may not eat well or keep up with prenatal visits, and, in the most severe cases they may be at increased risk for suicide.
Like many drugs, antidepressants fall into a gray area during pregnancy, with insufficient evidence to definitively prove the harms or benefits. Often, doctors may reserve drugs for women with more severe depression.
Berard and colleagues studied singleton births in Quebec from 1998 to 2009, examining prescription records for the mothers as well as medical records for their babies.
Overall, about 3 percent of the babies were exposed to antidepressants in utero. Among this group, 89 percent had exposure during the first trimester and 54 percent had exposure later in pregnancy.
During an average follow up of more than six years, 1,054 children – 0.7 percent of the total – were diagnosed with autism. The majority of them were boys.
Among the 2,532 infants exposed to antidepressants during the second or third trimester, 1.2 percent were diagnosed with autism.
The increased risk was limited to a family of antidepressants known as selective serotonin reuptake inhibitors (SSRIs) that includes drugs such as Paxil, Prozac, Zoloft and Celexa. SSRIs were linked to a more than doubled risk of autism.
Treatment with a combination of antidepressants during the second or third trimester was associated with more than quadrupled odds of autism, though the study included just five of these infants.
One shortcoming of the study is that it didn’t control for the severity of maternal depression, making it difficult to assess whether the increased autism risk might be tied to the underlying disease instead of the drugs used for treatment. It also didn’t account for the doses women were taking.
“In general, women who receive treatment are likely to have more severe and recurrent illness,” said Dr. Roy Perlis, a psychiatry researcher at Harvard University and Massachusetts General Hospital in Boston who wasn’t involved in the study.
The heightened risk in the rare instances when women took multiple types of antidepressants in the study might be because this treatment is reserved for women with the most severe symptoms, Perlis added by email. This may indicate that the increased autism risk is tied to the severity of depression, not to the medication.
Pregnant women who do take SSRIs should be reassured by the findings from this study and others that suggest the added autism risk linked to these drugs is only about one additional case in every 200 births, said Dr. Bryan King, Director of Seattle Children’s Autism Center and co-author of an accompanying editorial, in email to Reuters Health.
"This study looked only at one developmental outcome and there is no control group that would enable us to capture all of the potential harm that might have been prevented with the choice to treat depression," King said. "It is important that women have full discussions with their health care providers about the complex interplay of risks and benefits associated with depression treatment."