OAKLAND, Calif., Oct. 23 (UPI) -- Depressed pregnant women have twice the risk of preterm delivery than pregnant women with no symptoms of depression, U.S. researchers said.
Lead author Dr. De-Kun Li of Kaiser Permanente's Division of Research in Oakland, Calif., found that pregnant women with symptoms of depression have an increased risk of preterm delivery, and that the risk grows with the severity of the depressive symptoms.
The findings, published online in the journal Human Reproduction, provide preliminary evidence that social and reproductive risk factors, obesity and stressful events may exacerbate the depression-preterm delivery link.
The study looked at 791 pregnant Kaiser Permanente members in the San Francisco areas from October 1996 to October 1998.
Researchers interviewed the women around their 10th week of pregnancy and found that 41 percent of the women reported significant or severe depressive symptoms. The women with less severe depressive symptoms had a 60 percent higher risk of preterm delivery -- defined as delivery at less than 37 completed weeks of gestation -- compared with women without significant depressive symptoms, and the women with severe depressive symptoms had more than twice the risk.
"Preterm delivery is the leading cause of infant mortality, and yet we don't know what causes it," Li said.