Infants exposed late in a pregnancy to a group of antidepressants known as selective serotonin-reuptake inhibitors are six times as likely as nonexposed infants to experience a heart and lung disorder called persistent pulmonary hypertension, according to a study published on Thursday in the New England Journal of Medicine, USA Today reports (Rubin, USA Today, 2/9). SSRIs include drugs such as Pfizer's Zoloft and Eli Lilly's Prozac, according to the New York Times (Carey, New York Times, 2/9). According to the Los Angeles Times, PPH is characterized by inadequate oxygen levels in the blood and in severe cases can result in deafness, neurological problems or death (Zarembo/Alonso-Zaldivar, Los Angeles Times, 2/9). According to the New York Times, an estimated 10% to 20% of PPH cases require the infant to be connected to an artificial lung (New York Times, 2/9). PPH occurs in one in 1,000 births, and most infants recover, the Los Angeles Times reports (Los Angeles Times, 2/9). Christine Chambers, an assistant professor at the University of California-San Diego, and researchers from Boston University and Harvard University between 1998 and 2003 looked at 377 women who had given birth to infants diagnosed with PPH. Researchers asked participants about their medical histories and any drugs they took while pregnant. The study finds that 3.7% of the infants had been exposed to SSRIs after 20 weeks' gestation, means exposed infants are six times as likely as nonexposed infants to be diagnosed with the condition (New York Times, 2/9). Researchers said no increased risk was found from SSRI use during the first half of pregnancy or in women taking other types of antidepressants (Nano, AP/Seattle Times, 2/8). Researchers wrote that SSRIs might deter the production of agents in newborns that assist blood vessels in dilation, causing insufficient absorption of oxygen and other respiratory problems.

Reaction
Sandra Kweder, deputy director of FDA's Office of New Drugs, in a news conference on Wednesday said the study's results were "very worrisome" and that the agency plans to search its database for more cases linking SSRIs to PPH, the New York Times reports. She added that the agency is considering whether to ask manufacturers to revise drug labels or conduct further studies to better determine the risk (New York Times, 2/9). Kweder said, "For many women, the small risk suggested by this study may be outweighed by their own personal need for treatment of a mental health condition" (AP/Seattle Times, 2/8).

Editorial
In an accompanying NEJM editorial, James Mills of the National Institute of Child Health and Human Development writes, "There is a pressing need" for a comparison between SSRIs and other forms of depression treatment to decide which are the "safest, the most effective and the best tolerated by pregnant women." Mills concludes that in the meantime, "clinicians and patients will need to consider the current findings ... with other available evidence and decide on an individual basis whether the risks associated with exposure to SSRIs outweigh the benefits of therapy" (Mills, New England Journal of Medicine, 2/9).