THURSDAY, Jan. 12 (HealthDay News) -- Women who use antidepressants called selective serotonin-reuptake inhibitors such as Prozac and Celexa during pregnancy run a slight risk of having an infant with high blood pressure in the lungs, a new Swedish study finds.

The condition, known as persistent pulmonary hypertension, can lead to shortness of breath and difficulty breathing. Although rare, severe disease is associated with heart failure, the investigators noted.

"Infants born to women treated with SSRIs in late pregnancy had a twofold increased risk [of] their infants having persistent pulmonary hypertension," said lead researcher Dr. Helle Kieler, head of the Centre for Pharmacoepidemiology at Karolinska University Hospital in Stockholm.

"The increased risk seemed to be a class effect of SSRIs, as risks for the specific SSRIs were of similar magnitude," she added.

Women taking SSRIs should be informed about the increased risk, but they should also be told that persistent pulmonary hypertension is a rare disease that affects fewer than two of 1,000 newborns, Kieler said.

"If possible, non-medical treatment for depression during pregnancy should be considered," she said. "For women where treatment with an SSRI is the only or best option, the choice of substance is of less importance."

Dr. Gideon Koren, director of the Motherisk Program at The Hospital for Sick Children at the University of Toronto and author of an accompanying journal editorial, said this finding does not prove that SSRIs cause persistent pulmonary hypertension.

"It is important that, before we scare pregnant women not to treat their depression in pregnancy, we ensure that the science overcomes its methodological limitations," he said.

"Most notably, the authors have chosen SSRIs as the potential cause for persistent pulmonary hypertension, while their results show that untreated depression can also do it," Koren said.

Based on these data, "we cannot yet conclude that use of SSRIs causes persistent pulmonary hypertension in some babies," he said.

The report was published in the Jan. 12 online issue of the BMJ.

For the study, Kieler's team collected data on more than 1 million births from 1996 and 2007 in Denmark, Finland, Iceland, Norway and Sweden.

Among the mothers, nearly 11,000 took SSRIs during late pregnancy and about 17,000 took them during early pregnancy. Most of these women were older and smoked, researchers reported.

In addition, more than 54,000 mothers had been previously diagnosed with mental problems, but were not taking any medication.

Among the women taking SSRIs, Kieler's group looked at the use of fluoxetine (Prozac), fluvoxamine (Luvox), citalopram (Celexa), paroxetine (Paxil), sertraline (Zoloft) and escitalopram (Lexapro).

Fluvoxamine was rarely used and none of the children with persistent pulmonary hypertension were exposed to it, the researchers noted.

Of the nearly 11,000 mothers who used an SSRI in late pregnancy, 33 babies (0.2 percent) were born with persistent pulmonary hypertension, the researchers found.

Of the more than 17,000 women who used SSRIs in early pregnancy, 32 babies (less than 0.2 percent) suffered persistent pulmonary hypertension, they added.

Among the 54,000 mothers who had previously been diagnosed with a mental problem but who did not take SSRIs during their pregnancy, 114 infants were born with persistent pulmonary hypertension, Kieler's group found.

Other factors such as Cesarean delivery or low birth weight were not associated with persistent pulmonary hypertension, they noted.

Another expert, Dr. Ilene Sosenko, a professor of pediatrics and neonatology at the University of Miami School of Medicine, said this study won't change clinical practice.

"The risk of persistent pulmonary hypertension is very low and even though there is a higher risk with SSRIs, the risk remains extremely low," she said. "From a clinical standpoint, the risk is not increased to the point where it would change the pattern of the way doctors are managing their pregnant women," she said.

Managing the depression is probably more important than worrying about the risk of persistent pulmonary hypertension, Sosenko said.

"Depression can impact on how the mother eats or whether she takes other drugs or whether she gets her prenatal care," she said. "Although there is a very small increased risk of persistent pulmonary hypertension, the benefit of remaining on SSRI medication is important."

More information

For more on depression during pregnancy, visit the American Pregnancy Association.