THE QUESTION Taking antidepressants during pregnancy has been considered risky. Do the potential problems, in particular the possibility of miscarriage, stem from the drugs or from the depression itself?

THIS STUDY analyzed data on 1,279,840 pregnant women in Denmark. During the first 35 days of pregnancy, 22,884 were taking an SSRI (selective serotonin reuptake inhibitor) antidepressant: fluoxetine (Prozac), citalopram (Celexa), paroxetine (Paxil) or escitalopram (Lexapro). Overall, 142,093 women in the full study group had a miscarriage — 12.6 percent of those taking SSRIs and 11.1 percent of those who never took them. Taking into account such things as age, income, education and previous miscarriages, women on SSRIs during their early pregnancy had a 27 percent increased risk for miscarriage. However, among women who once took SSRIs but stopped taking them from three months to a year before becoming pregnant, 13.8 percent had a miscarriage, which the researchers said equaled a 24 percent higher risk for miscarriage than that of those who never took SSRIs. Because the increased risk of miscarriage was nearly the same for women who took antidepressants early in pregnancy as it was for those who discontinued their use before becoming pregnant, the researchers noted that the findings suggest “no causal relationship between SSRIs and miscarriage.” Instead, they wrote, depression itself or lifestyle factors such as alcohol use, smoking or not taking recommended folic acid supplements might explain the increased likelihood of miscarriage.

WHO MAY BE AFFECTED? Women who take SSRIs, the most commonly prescribed antidepressants. They work by blocking the reabsorption (reuptake) of serotonin, a neurotransmitter that helps brain cells send and receive chemical messages. Changing the balance of serotonin in the brain acts as a mood-booster. Though SSRIs generally have fewer side effects than older types of antidepressants, experts warn that they could harm the child when taken during pregnancy or while breast-feeding, or cause pregnancy complications.

A study says that other factors, such as depression itself, drinking or smoking are more likely to increase miscarriage risks. (iStock)

CAVEATS Data on SSRI use came from records of filled prescriptions. The study examined no risks other than miscarriage. In discussions with their doctors, women who are depressed and considering pregnancy should weigh the risks of taking SSRIs against the risks of stopping treatment.

FIND THIS STUDY October issue of Obstetrics and Gynecology, at journals.lww.com/greenjournal/pages/default.aspx (click on “Published Ahead of Print”).

LEARN MORE ABOUT SSRI antidepressants at www.mayoclinic.org. Learn about depression at nimh.nih.gov/health.

The research described in Quick Study comes from credible, peer-reviewed journals. Nonetheless, conclusive evidence about a treatment's effectiveness is rarely found in a single study. Anyone considering changing or beginning treatment of any kind should consult with a physician.