Boston, MA - Women who take selective serotonin-reuptake inhibitors (SSRIs) during late pregnancy may be at increased risk for gestational hypertension, new research suggests [1].

Investigators also found that compared with pregnant women never treated with SSRIs, those who stopped taking SSRIs before the end of their first trimester had a 1.4-fold increased risk for preeclampsia and those who continued taking SSRIs had a 4.9-fold increased risk for preeclampsia.

These findings suggest that "women who are exposed to SSRIs during pregnancy should be carefully monitored for the occurrence of gestational hypertension and preeclampsia," Sengwee Toh (Harvard School of Public Health, Boston, MA) and colleagues write.

"More studies are needed to separate the effects of treatment with SSRIs from those of underlying disorders," Toh said.

The study is published online January 2, 2009 in the American Journal of Psychiatry.

Studies estimate that up to one in four pregnant women shows signs of depression and up to 13% of pregnant women are treated with antidepressants, most commonly SSRIs.

"The benefits of treating depression during pregnancy and the risk of relapse associated with treatment discontinuation are well described," the authors note.

On the other hand, first-trimester exposure to certain SSRIs has been linked with specific birth defects, and a few studies have linked depression with risk for preeclampsia, but it is unknown whether this is due to antidepressant medication.

Pregnant women treated with antidepressants "often struggle, along with their doctors, with the decision about treatment options, and a critical question is whether to continue or discontinue antidepressant treatment during pregnancy," the researchers write.

In the first study to investigate a potential link between the risk for gestational hypertension and preeclampsia and continuing or discontinuing antidepressants beyond the first trimester, the researchers analyzed data from the Slone Epidemiology Center Birth Defects Study.

Study participants included 5731 women without pregestational hypertension who gave birth to nonmalformed babies between 1998 and 2007.

The study divided the women into three groups:

• 5532 women who were not exposed to SSRIs.
• 107 women who had been taking SSRIs two months before pregnancy and stopped by the end of the first trimester.
• 92 women who had been taking SSRIs two months before pregnancy and continued treatment beyond the first trimester.

The women were asked whether a healthcare professional had diagnosed them with high blood pressure or preeclampsia during pregnancy.

The study outcomes were gestational hypertension with or without preeclampsia.

SSRI treatment two months before pregnancy was associated with an increased risk for gestational hypertension (with or without preeclampsia), especially among women who continued their SSRI exposure.

Gestational hypertension occurred in 9% of the women who were not treated with SSRIs, 13.1% of the women who stopped their SSRI treatment before the third trimester, and 26.1% of the women who continued treatment beyond the first trimester.

Preeclampsia developed in 2.4% of the women who were not treated with SSRIs, 3.7% of the women who were exposed to SSRIs only in the first trimester, and 15.2% of women who continued their SSRI treatment beyond the first trimester.

These data suggest that "SSRI exposure during late pregnancy—whether causal or not—might identify women who are at increased risk for gestational hypertension and preeclampsia."

However, the investigators caution that the study can only assess risk and does not shed any light on the potential benefit of SSRI treatment during pregnancy.