Postpartum depression risk may lurk in your genes, UNC-Chapel Hill study confirms

New evidence from UNC School of Medicine researchers confirms that postpartum depression can be inherited, potentially opening up new avenues for screening and treating the most common pregnancy complication.

This study, which includes data from tens of thousands of women, is the largest genomic analysis to find specific regions of DNA associated with postpartum depression, bolstering the case that certain genetic characteristics can increase the risk of developing the condition.

This confirms past findings from smaller studies with identical twins and genomic analyses.

This finding has big implications for detecting and treating postpartum depression, said Dr. Samantha Meltzer-Brody, an author of the paper and chair of psychiatry at the UNC School of Medicine.

Researchers believe the disorder’s onset is likely caused by a combination of genetic and environmental factors, like sleep deprivation and anxiety from caring for a newborn. Meltzer-Brody said screening for a family history of postpartum depression could help physicians identify which patients should be more carefully monitored.

“Right now, in many clinical settings, we do not obtain this type of psychiatric history,” she wrote in an email to The N&O. “We should be taking a much more proactive stance with anyone who has a history...”

Postpartum depression affects about 15% of women. In some cases, PPD can lead to grave consequences — about a fifth of maternal deaths after childbirth are due to suicide.

Jerry Guintivano, also a UNC faculty member and the lead author of the paper published in the American Journal of Psychiatry, said their study also aimed to tackle a slightly more complicated question: what about someone’s genetics predisposes them to postpartum depression?

To answer, researchers combed through genetic data from people diagnosed with postpartum depression and compared them to data from women without the disorder.

Guintivano, who specializes in the genetics and epigenetics underlying postpartum depression, said while everyone has a certain amount of variation in their genetic code, in certain combinations those variants can create a predisposition to psychiatric disorders.

Guintivano said the analysis also potentially gives a genetic explanation for why the first medication prescribed specifically for postpartum depression works. Brexanolone, which was approved in pill form earlier this year for PPD, acts on a certain type of brain cells called GABAergic neurons.

When researchers looked at the genetic variants associated with PPD, they found changes in the areas associated with that same type of brain cell. In a way, Guintivano said this finding independently confirms that this medication is targeting the right pathways.

“It was just sort of me working in my silo and it just happened that it converges with some of the work that they do,” he said.

Insights into other psychiatric disorders?

Better understanding the biology of postpartum depression may help scientists understand other psychiatric disorders, Guintivano said.

In this study, UNC researchers found the genetic markers associated with PPD overlapped with genetic markers of clinical depression in general.

“We find that it is very similar — it’s almost the same thing,” he said.

This has significant implications for the treatments of both disorders, he said. First, he said it may explain why some treatments for major depression could be effective at treating postpartum depression. Meltzer-Brody added that it also suggests a history of depression prior to pregnancy increases the risk for postpartum depression.

Maybe more significantly, this makes a compelling argument that understanding the underlying causes of postpartum depression could offer a window into understanding depression more generally, he said.

Unlike major depression, which can affect a wide variety of people in many different ways, postpartum depression occurs in a narrow group of women and begins at a predictable time — shortly after childbirth — which makes it less complicated to study, he said.

“This could help sort of figure out what is potentially causing the onset of general depression,” he said.

Teddy Rosenbluth covers science and health care for The News & Observer in a position funded by Duke Health and the Burroughs Wellcome Fund. The N&O maintains full editorial control of the work.

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