Depressed moms-to-be are more likely than nondepressed women to have a preterm birth, and the worse their mood, the greater their risk, says a new study published in Human Reproduction. In fact, women in the study who were severely depressed during early pregnancy more than doubled their risk of giving birth to premature babies.
About 12.5 percent of babies born in the U.S. each year are preterm, according to the March of Dimes
The reasons why aren't entirely clear, but the researchers don't think antidepressants are to blame. Only 1.5 percent of women were taking the drugs during pregnancy, and excluding them from the study didn't change the results.
Depressed women who are pregnant, or planning to become pregnant, should get help, says De-Kun Li, M.D., Ph.D., the lead study author and a reproductive and perinatal epidemiologist at Kaiser Permanente's Division of Research in Oakland, California
"Don't think, 'This is just part of being pregnant, this is my hormones doing something,'" he says, adding that depression relief doesn't always have to include medication. "Getting the emotional and physical support of your family members can significantly alleviate symptoms of depression." Health.com: How social support can help your postpartum depression
About 12.5 percent of babies born in the United States each year are preterm, which means that they are delivered within the first 37 weeks of pregnancy, according to the March of Dimes. (A typical pregnancy is 40 weeks.)
These tiny babies can have a host of medical and learning problems. But despite decades of research, doctors still have no surefire way to determine who's at risk of preterm delivery; nor do they understand why it happens or how to prevent it.
Treating depression might be one way to help prevent these premature births, according to Dr. Li.
"Depression during pregnancy really has not been paid attention to," Dr. Li says. "It's definitely underdiagnosed, undertreated, and frequently dismissed and ignored." Health.com: Bipolar disorder is different for women
In the study, Dr. Li and his team interviewed 791 women between 6 and 18 weeks of pregnancy. All were members of the Kaiser Permanente Medical Care Program, a managed-care plan. About 41.2 percent were at least "significantly" depressed, and 21.7 percent had severe depression.
After taking other risk factors into account (such as a mother's age, education level, and whether she had a preterm baby in the past), the study found that women who were depressed were 1.6 times more likely to give birth prematurely than women with so-called normal moods. Women who were severely depressed were at 2.2 times the risk for preterm delivery.
Women with less education, past fertility problems, at least two previous pregnancies, or a history of stressful life events were most at risk for a depression-related preterm birth. Health.com: Your risk of postpartum depression after future pregnancies
Dr. Li and his team don't know why depression might influence preterm birth risk. However, past research has linked stress to poor pregnancy outcomes through effects on hormones, the immune system, and other factors.
"Women who are depressed also have a lot of other factors that can put them at risk for preterm birth," notes Diane Ashton, M.D., deputy medical director of the March of Dimes in White Plains, New York. For example, she explains, they tend to eat poorly and are more likely to smoke.
"What I tell my patients is that they need to be well during pregnancy," says Diana L. Dell, M.D., an assistant professor in obstetrics and gynecology as well as psychiatry at Duke University in Durham, N.C. "That's what the study is basically showing us."
Pregnancy itself doesn't seem to increase the chance of depression. About 15 to 16 percent of women are depressed during pregnancy -- no more than the general population, Dr. Dell says.
"Women are willing to make incredible sacrifices for their children, and they endure all sorts of discomforts during pregnancy," she adds. But because depression and anxiety can have health consequences for both a mother and her child, Dr. Dell says, they should not be endured, but treated.
For women with mild to moderate depression, therapy is often enough, according to Dr. Dell. But medication might be necessary for women with more severe depression.
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