May 21, 2013
Researchers Link Two Genes To Postpartum Depression
Lee Rannals for redOrbit.com — Your Universe OnlineJohns Hopkins Medicine team studied 52 pregnant women to determine what factors to consider when attempting to predict whether someone will experience postpartum depression. They found that epigenetic modifications can be detected in the blood of pregnant women during any trimester, potentially providing a simple way to foretell depression in the weeks after giving birth.
"Postpartum depression can be harmful to both mother and child," says study leader Zachary Kaminsky, Ph.D., an assistant professor of psychiatry and behavioral sciences at the Johns Hopkins University School of Medicine. "But we don't have a reliable way to screen for the condition before it causes harm, and a test like this could be that way."
Scientists are not sure exactly what causes postpartum depression, but they are sure of the conditions it comes with, such as feelings of sadness, hopelessness, exhaustion and anxiety. Doctors say ten to 18 percent of all new mothers develop the condition, and the rate rises from 30 to 35 percent among women with previously diagnosed mood disorders.
Scientists believe the symptoms were related to a large drop-off in the mother's estrogen level following childbirth, but other studies have disproved that.
The Johns Hopkins team studied mice and found estrogen induced epigenetic changes in cells in the hippocampus. They then created a complicated statistical model to find the candidate genes most likely undergoing those epigenetic changes. The researchers later confirmed their findings in humans by looking for epigenetic changes in thousands of genes in the blood samples of pregnant women with mood disorders.
Researchers noticed that women who developed postpartum depression exhibited stronger epigenetic changes in genes that are most responsive to estrogen. They found that two genes were most highly correlated with the development of postpartum depression, TTC9B and HP1BP3. These genes were able to predict with 85 percent certainty which women would experience postpartum depression.
"We were pretty surprised by how well the genes were correlated with postpartum depression," Kaminsky says. "With more research, this could prove to be a powerful tool."
He said the next step in the research is to collect blood samples from a larger group of pregnant women and follow them for a longer period of time. He also said it would be useful to examine whether the same epigenetic changes are present in the offspring of women who develop postpartum depression.
Kaminsky believes their findings could be used to help screen women who may experience postpartum depression, and potentially give the care needed beforehand.
Another group of researchers writing in BJOG said earlier this month that women with unintended pregnancy are more likely to suffer from postpartum depression. University of North Carolina researchers found that women with unintended pregnancies were four times more likely to suffer from postpartum depression.