While post-partum depression "has long been recognized as a serious public health problem," Kaiser Permanente researchers write in an article published Thursday in the journal Human Reproduction, "depression during pregnancy has not been well-studied." It's not clear how common depression is in pregnant women and how it affects their babies, the authors write.
A total of 791 women completed the screening and delivered a live baby. Women who, after being screened, went on to miscarry — defined as a pregnancy loss before 20 weeks' gestation — were excluded from the analysis.
Overall, after accounting for other factors that might play a role, women with significant depressive symptoms were nearly twice as likely to deliver a baby preterm — or before 37 complete weeks' gestation — than those without significant depressive symptoms. The more severe the women's depression, the greater their risk of delivering preterm, the study found.
The authors speculate that depression during pregnancy might interfere with placental hormones that help maintain a healthy pregnancy and ensure that labor doesn't start too early. In addition, they write, their study suggests that low education level and stressful events could exacerbate the effect of depressive symptoms on the risk of preterm delivery.
Few women studied were prescribed antidepressants while pregnant, which the authors call a strength of their research, because some studies have suggested a link between antidepressants themselves and preterm delivery. But, Li said, "overall, the safety of antidepressant use during pregnancy is uncertain."
Non-drug approaches, such as "reaching out to other pregnant women, family and friends, asking for the care and connections they need," is often enough to improve pregnant womens' mood, says obstetrician/gynecologist Tracy Flanagan, director of women's health at Kaiser Permanente, who was not involved with the study.
"Antidepressants are usually not a first-line treatment" in pregnancy, Flanagan says, "but antidepressants are very useful for people who have severe depression and even moderate depression, in some cases."