New research suggests that infants of mothers who are in the late stages of pregnancy and who take a class of antidepressants called selective serotonin reuptake inhibitors may be at increased rick of developing high blood pressure in the lungs – known as persistent pulmonary hypertension.

The research team, led by Sophie Grigoriadis of the Sunnybrook Health Sciences Centre in Ontario, Canada, published their findings in the BMJ.

The investigators note that although previous research has analyzed the association between selective serotonin reuptake inhibitor (SSRI) intake and persistent pulmonary hypertension of the newborn (PPHN), the results have been unclear.

To investigate further, the researchers assessed seven studies that analyzed the association between PPHN and antidepressant use during pregnancy.

The research team notes that data was only available for SSRIs, therefore other classes of antidepressants were excluded. They also took into account other known risk factors for PPHN.

From the analysis, the investigators found that infants who were exposed to SSRIs during the late stages of their mother’s pregnancy demonstrated an increased risk for PPHN.

But the authors do emphasize the fact that the risk of PPHN remains low. They note that only 2 infants in every 1,000 are likely to develop the condition.

Furthermore, they estimate that in order to see one additional case of PPHN, between 286 and 351 women would need to be treated with SSRIs in the late stages of pregnancy.

No increased risk of PPHN was associated with SSRI exposure in the early stages of pregnancy.

However, the research team says that although the increase in risk of PPHN is small as a result of SSRI exposure during late pregnancy, education and counseling should be offered to pregnant women using or considering the use of selective serotonin reuptake inhibitors (SSRIs).

“It is imperative that the mother’s health be weighed heavily in treatment decisions; she and her family must be counseled on both the risks of exposing the fetus to antidepressant drugs and the risks of severe depressive illness,” they write.

The researchers add:

Pregnant women considering or using SSRIs and their families should be educated about persistent pulmonary hypertension of the newborn, how the symptoms can range in severity, what treatments are available for it at the institution where the birth will take place, and that it can typically be managed successfully if it does occur in the context of SSRI use.”

They note that further research should analyze whether other types of antidepressants may increase PPHN risk if taken during pregnancy.

This is not the first study to link SSRI use during pregnancy to poor birth outcomes. In November 2012, Medical News Today reported on a study suggesting that pregnant women who take SSRIs may increase the risk of preterm birth, miscarriage, and even long-term neurobehavioral health conditions, such as autism.