Oct. 24 -- THURSDAY, Oct. 23 (HealthDay News) -- Women who are depressed early in their pregnancy run a higher risk of preterm delivery, the leading cause of infant mortality, a new study suggests.
For the study, researchers interviewed 791 San Francisco-area women near their 10th week of pregnancy. Forty-one percent reported "significant" symptoms of depression, and 22 percent reported "severe" symptoms.
Those women with severe symptoms had almost twice the risk of an early birth, defined as before 37 weeks' gestation. Those with significant symptoms had a 60 percent risk of early birth, the study found.
Women who were likelier to report depressive symptoms tended to be younger than 25, unmarried, less educated, poorer, black, and have a history of preterm delivery.
Discovering a possible cause of preterm birth, about which little is known, makes the findings significant, said study lead author Dr. De-Kun Li, a perinatal epidemiologist and senior research scientist at Kaiser Permanente's Division of Research in Oakland, Calif.
Scientists have been researching for the causes of high rates of infant mortality in the United States, Li said, but, "we don't know what is going on. If we can find something as obvious as depression that can be treated during pregnancy, that is very, very significant."
The findings were published online Oct. 23 in the journal Human Reproduction.
Dr. Shari I. Lusskin, director of reproductive psychiatry at New York University Medical Center, said she doesn't think the study establishes a link between depression in early pregnancy and preterm delivery. She said the women in the study weren't clinically diagnosed with depression but had scored high on a screening test.
"We don't know if the depression at 10 weeks is a marker for something that happens later in pregnancy, which is the real culprit," she said.
Li hopes the study's findings will make "ante-natal depression" as widely recognized as postpartum depression has become. Until now, depression during pregnancy has been "under-estimated and under-treated," he said, "not just by women, but also by their doctors."
One reason for this lack of attention is that there hasn't been strong evidence of a connection between depression in pregnant women and harm to the fetus, Li said.
Women may not readily report depressed feelings when they are pregnant because of the societal expectation that having a baby should be a joyous occasion, said Dr. Jennifer Wu, an obstetrician and gynecologist at Lenox Hill Hospital in New York City.
"I think many patients are very stressed about pregnancy and worried about the pregnancy and not sure about its impact on their lives," Wu said.
Lusskin tries to spread the word about the dangers of depression during pregnancy.
"The more we know about postpartum depression, the more we realize that half the cases started in pregnancy," Lusskin said. Ante-natal depression also carries the risk of noncompliance with prenatal care, poor nutrition, inadequate sleep, self-medication with drugs and alcohol, and suicide, she explained.
And, Lusskin added, "Ante-natal depression interferes with bonding with the baby both during pregnancy and post-partum."
The take-home lesson from the Kaiser study, Lusskin said, "is that ante-natal depression and ante-natal depression symptoms have some effect on pregnancy, and they should be treated, even though we don't know how that mood is translated into the biochemistry of that pregnancy."
She added that she is "a proponent of maintaining a good mood throughout pregnancy and breast-feeding, and doing what you have to do to do that. If a patient requires medication, she should do that. Then, it's a matter of finding the drugs that are best studied and most effective for the patient."
To learn more about pregnancy and depression, visit the American Pregnancy Association.
SOURCES: De-Kun Li, M.D., Ph.D., reproductive and perinatal epidemiologist and senior research scientist, Kaiser Permanente's Division of Research, Oakland, Calif.; Shari I. Lusskin, M.D., director of reproductive psychiatry, New York University Medical Center, New York City; Jennifer Wu, M.D., obstetrician and gynecologist, Lenox Hill Hospital, New York City; Oct. 23, 2008, Human Reproduction, online