Antidepressant use during pregnancy and high blood pressure

Use of selective serotonin re-uptake inhibitor (SSRI) antidepressants during pregnancy appears to be linked with increased risk of pregnancy induced high blood pressure ("hypertension"), but a causal link has not been established.

Pregnancy hypertension is sometimes linked with pre-eclampsia, a serious condition that can harm pregnant women and their unborn babies. But the authors stress that pregnant women should not stop taking their prescribed medication; instead they should seek a consultation with their doctor if they are concerned.

Out of 1,216 women, the overall incidence of hypertension in women taking SSRIs appeared to increase from about 2% to about 3.2% (a relative risk increase of 60%). One specific SSRI, paroxetine, was associated with an increase in incidence of hypertension to about 3.6% (an 81% increase).

"These results are an early indicator of risk attributable to antidepressant drug treatment above that which may be attributed to depression or anxiety disorders in the absence of drug treatment," says senior researcher, Dr Anick Bérard who is Director of the research unit of medications and pregnancy at CHU Ste-Justine's Research Center, and professor at the Faculty of Pharmacy at the University of Montreal, Quebec, Canada. The research has just been published in the British Journal of Clinical Pharmacology.

The issue is particularly important given that antidepressants are one of the most commonly used medications during pregnancy. Up to 20% of pregnant women are affected by depression and anywhere between 4% and 14% of pregnant women frequently use anti-depressants.

The study drew data from the Quebec Pregnancy Registry and compared 1,216 women who had been diagnosed with pregnancy-induced hypertension with or without pre-eclampsia and with no history of hypertension before pregnancy, with 12,160 matched controls.

"Pregnancy induced hypertension is a serious condition that can directly affect the mother and her unborn baby. Although a few other studies on the same topic have been performed before, our study is the only one that looks at the class and type of antidepressant and the risk of pregnancy induced hypertension," says Bérard.

The message, however, is not as simple as telling pregnant women to stop taking antidepressants, because once a woman is using them, discontinuation during pregnancy is associated with an increased risk of depressive relapses and post-partum depression. "Individual decisions have to be made one woman at a time, and risks and benefits have to be evaluated carefully in consultation with a doctor; there is no 'risk zero'," says Dr Bérard.

"This research adds another piece of evidence and shows the importance of fully assessing the risks and the benefits of antidepressant use during pregnancy for the mother and child," says Bérard.

Anyone affected by this study should not stop taking their prescribed medication but seek a consultation with their doctor if they are concerned.