Antidepressants in pregnancy increase risk of miscarriage

A new study published in the Canadian Medical Association Journal found a 68 percent increase in the overall risk of miscarriage in pregnant women using antidepressants. Antidepressants are widely used in pregnancy and up to 3.7 percent of women use them at some point during the first trimester.

Discontinuing treatment can result in a depressive relapse which can put mother and baby at risk. Previous studies on antidepressant use in pregnancy did not examine miscarriages as a main outcome, had small samples and several showed contradictory results. This large study sought to determine the association between antidepressant use in pregnancy, treatment classes, types and doses, and risk of miscarriage.

Researchers from the Université de Montréal and the Sainte-Justine University Hospital Research Center looked at data on 5,124 women in Quebec from a large cohort of pregnant women who had clinically verified miscarriages up to 20 weeks of gestation and a large sample of women from the same Registry who did not have a miscarriage. Of those who miscarried, 284 (5.5 percent) had taken antidepressants during pregnancy.

Selective serotonin reuptake inhibitors (SSRIs), especially paroxetine and also venlafaxine, were associated with increased risk of miscarriage as were higher daily doses of either antidepressant. As well, a combination of different antidepressants doubled the risk of miscarriages.

"These results, which suggest an overall class effect of selective serotonin reuptake inhibitors, are highly robust given the large number of users studied," says Dr Annick Bérard, a professor of pharmacy at the Université de Montréal and director of the Research Unit on Medications and Pregnancy at the Sainte-Justine University Hospital Research Center.

The research team urges physicians to discuss the risks and benefits of treatment to all patients of childbearing age who are taking antidepressants or among pregnant patients who require antidepressant therapy during early pregnancy.

(Source: University of Montreal: Canadian Medical Association Journal: June 2010)