Exposure to a certain class of antidepressant medications during pregnancy may be associated with an increased risk of preterm birth, a low five-minute Apgar score and admission to the neonatal intensive care unit, according to a report in the October issue of Archives of Pediatrics & Adolescent Medicine, one of the JAMA/Archives journals.

More than one in ten pregnant women are estimated to have depression, comparable in frequency and severity to postpartum depression, according to background information in the article. "Depression, antidepressants and lifestyle factors associated with depression may influence pregnancy outcomes and newborn health," the authors write. "The safety profile of antidepressant medication in pregnancy is undetermined, but depression during pregnancy can be serious and has been associated with an increased maternal mortality." Selective serotonin reuptake inhibitors (SSRIs) have been used during pregnancy since the early 1990s and are recommended as the first choice for pregnant women in many countries.

Najaaraq Lund, M.D., of the Bandim Health Project, Indepth Network, Bissau, Guinea-Bissau, and Aarhus University, Aarhus, Denmark, and colleagues studied women receiving prenatal care from 1989 to 2006. They compared birth outcomes including gestational age, birth weight and Apgar score among babies born to 329 women who were treated with SSRIs, 4,902 who had a history of psychiatric illness but were not treated with SSRIs and 51,770 who had no history of psychiatric illness.

Women who took SSRIs during pregnancy gave birth an average of five days earlier and had twice the risk of preterm delivery as women with no history of psychiatric illness. Infants exposed to the medications in utero were significantly more likely than the two groups not exposed to have a five-minute Apgar score of seven or below or to be admitted to the neonatal intensive care unit (NICU). Head circumference and birth weight did not differ between the three groups.

SSRIs have been shown to readily cross the placenta and appear in the umbilical cord blood of infants whose mothers took them, the authors note. Several previous observations have described withdrawal symptoms in infants born after exposure to the medications. In this study, exposed infants admitted to the NICU experienced symptoms that could be due to withdrawal from or adverse effects of SSRIs, including jitteriness, seizures, respiratory problems, infections and jaundice.

"The study justifies increased awareness to the possible effects of intrauterine exposure to antidepressants," the authors conclude. "However, treatment of depression during pregnancy may be warranted and future studies need to distinguish between individual SSRIs to find the safest medication."

The study was conducted at Perinatal Epidemiology Research Unit, Skejby, Denmark. Dr. Lund was supported by a one-year research scholarship from the Danish Medical Research Council.