SSRIs raise risk of newborn pulmonary hypertension

March 1, 2012

Although the risk for persistent pumonary hypertension (PPH) in newborns is low (ie, 2 per 1,000 live-born infants), selective serotonin reuptake inhibitors (SSRIs)taken by mothers after the 20th week of pregnancy more than double the risk for this life-threatening condition, according to the findings of a Nordic population-based cohort study.

Although the risk for persistent pulmonary hypertension (PPH) in newborns is low (ie, 2 per 1,000 live-born infants), selective serotonin reuptake inhibitors (SSRIs) taken by mothers after the 20th week of pregnancy more than double the risk for this life-threatening condition, according to the findings of a Nordic population-based cohort study.

Researchers from Sweden, Finland, Norway, Denmark, and Iceland used health registry data on more than 1.6 million infants born after the 33rd week of pregnancy during the years 1996 to 2007. Among approximately 30,000 women who were dispensed SSRIs during pregnancy, about 11,000 used them after the 20th week of gestation; 33 of their newborns, or about 3 per 1,000 live-born infants, had PPH. Of the approximately 17,000 babies exposed to SSRIs in early pregnancy, 32 had PPH. The corresponding figure for the 158,840 never exposed was 1,935 (1.2 per 1,000 live-born infants).

All of the SSRIs studied (ie, sertraline, citalopram, paroxetine, fluoxetine, fluvoxamine, and escitalopram) had similar risks, suggesting a class effect. In addition, taking SSRIs before the 6th week of pregnancy also slightly increased the risk for PPH: adjusted odds ratio 1.4 (95% CI, 1.0-2.0). Although the mechanism by which SSRIs influence the development of PPH is unknown, experts suspect the accumulation of SSRIs in the lungs, combined with the potential of serotonins to induce vasoconstriction and to mediate pulmonary arterial smooth muscle cell proliferation through the serotonin transporter, has something to do with it.