Levels of a certain stress hormone released by the placenta may be able to predict a woman’s risk of developing postpartum depression, according to a new study presented at the annual meeting of the American Psychiatric Association.
Mothers who show high levels of the hormone—called placental corticotropin-releasing hormone (pCRH)—around the middle of their pregnancies (at 25 weeks) are more likely to be depressed three months after giving birth, compared with women whose levels are lower.
“Women who show high levels of this hormone prenatally are at increased risk,” said study co-author Laura Glynn, Ph.D., a psychologist at Chapman University in Orange, Calif.
The placenta produces varying amounts of the hormone pCRH over the course of pregnancy, with a sharp increase just before birth. Experts believe the hormone plays a role in timing when women deliver their babies.
For instance, women who deliver prematurely tend to have higher levels of pCRH than those who deliver at term. “It’s been called the placental clock,” said Glynn.
For the study, researchers measured hormone levels in the blood of 170 pregnant women at 15, 19, 25, 31 and 36 weeks of gestation. (Full-term pregnancies last 40 weeks.) The researchers also assessed the women’s levels of depression at three and six months after giving birth.
Women with high levels of pCRH around the middle of their pregnancies (at 25 weeks) were more likely to suffer from depression three months after giving birth, compared with women with low levels.
The researchers didn’t find a link between pCRH levels and depression at the six-month mark.
The research could help identify women who are at risk of postpartum depression before they give birth so that health care professionals could intervene early. It’s particularly important to identify the risk early on because postpartum depression can have long term effects.
“Not only is mom suffering, but her suffering is going to influence the development of the infant in a pretty profound way,” Glynn said.
The study shows an association, not a cause-and-effect relationship, between pCRH levels and postpartum depression. It is still unclear why high pCRH levels might predict the risk of depression, but Glynn said it could be that some women’s hormonal systems take longer to return to their pre-pregnant states.
The study also suggests that postpartum depression that appears just after birth may have different causes than depression that shows up later on.
Source: American Psychiatric Association