An estimated 10 percent to 20 percent of pregnant women will develop postpartum depression, a condition that plagues new mothers with persistent feelings of sadness, hopelessness, exhaustion and anxiety that can last up to a year after giving birth. In women with a history of mood disorders such as depression and bipolar disorder, the rates rise to 35 percent to 40 percent.
Until now, there has been no reliable way to screen for postpartum depression in advance. But new research by Zachary Kaminsky, Ph.D., an assistant professor of psychiatry and behavioral sciences at the Johns Hopkins University School of Medicine, may change that. A study of 50 women with a history of mood disorders revealed that a simple blood test during pregnancy can determine genetic predictors of postpartum depression with 85 percent accuracy.
Kaminsky says the data indicated that women at risk were more sensitive to estrogen. This is determined by studying epigenetic codes — marks on DNA that affect how genes respond. "We can take blood during pregnancy, and we can look for these marks and have a pretty accurate guess as to whether a woman's going to get postpartum depression or not," he says.
While the test is likely a few years away from being available to the public, these findings provide hope that someday postpartum depression will affect far fewer moms. "There are 6 million pregnancies a year in the U.S. That's 600,000 women who are being affected by this," Kaminsky says. "And it's preventable. With therapy and treatment, it can be avoided. That's why knowing ahead of time can really be helpful."