Researchers say that a blood test may soon identify which pregnant women are at highest risk of developing postpartum depression, so they can seek treatment that could control their symptoms.
Up to 20% of new mothers may experience feelings of anxiety, hopelessness, and sadness after giving birth, but doctors don’t have a reliable way of predicting which expectant moms are most vulnerable. While those with a history of mood disorders may have a slightly higher risk of feeling postpartum depression, in most cases there are few signs that foretell which women will develop the disorder in the weeks and months after they deliver.
But in a small study of 52 pregnant women described in the journal Molecular Psychiatry, researchers at the Johns Hopkins University School of Medicine found changes in certain genes, which they could pick up in the blood, that distinguished women who went on to suffer from postpartum from those who did not. The genetic changes were epigenetic modifications, which means they were not permanent alterations in the women’s genomes but instead reflected differences in the way these genes were activated.
The scientists, led by Zachary Kaminsky, a professor of psychiatry and behavioral sciences at Hopkins, were inspired to look for the genetic changes after studies in mice. They found that estrogen
, which increases during pregnancy, triggers changes in the hippocampus, a region of the brain
that’s responsible for memory and mood, and that two genes were affected in particular. Not much was known about these snippets of DNA, except that they played some role in processes that are important for regulating mood — such as adapting to new environments and reorganizing neural circuits to make such accommodations possible.
It turned out the same genes were affected in women who experienced postpartum depression as well, and Kaminsky and his colleagues believe that the genes made the women more sensitive to the dramatic drop in estrogen that occured after birth. Without the estrogen, the genes may not have been as active, which could have contributed to the depressed mood that these women felt following delivery. Based on the levels of compounds made by these genes that could be picked up in the blood, these two genetic markers predicted with 85% accuracy which pregnant women went on to develop postpartum depression, and which ones did not.
To confirm the findings, Kaminsky says the test should be validated in a larger group of pregnant women who are followed for a longer period of time, but he hopes that this genetic test will identify women at highest risk — at any time during their pregnancy — and allow them to take advantage of treatments that could prevent the worst symptoms of depression. He and his colleagues have already filed a patent application for the two genes and their potential for identifying postpartum risk. “We are actively looking for partners to try to develop this finding further into a clinically useful tool,” he says. Prior research showed that recognizing and treating postpartum depression early can prevent the disorder from becoming debilitating for mothers and becoming a long term problem — for both them and their babies.