(ORDO NEWS) — Postpartum depression is thought to affect about 15 percent of women after childbirth and can negatively affect babies, but we still don’t fully understand why it occurs in the first place. A new study has identified a potential link to the human immune system.
A team led by researchers from Virginia Commonwealth University looked at multiple characteristics of blood samples from 482 women with postpartum depression (PPD for short) and found significant differences in B cells compared to women without the condition.
B cells are a key part of the body’s immune system, activated when the body recognizes foreign objects; in response, these cells are among the main producers of antibodies. B cells also send both pro- and anti-inflammatory signals.
“During pregnancy, the immune system interacts very delicately,” says geneticist Jerry Guintivano of the University of North Carolina.
“She has to prevent infection from a cold, and also fine-tune herself so that she doesn’t recognize the fetus as a foreign body and attack it.” Then, in the postpartum period, all of these hormones and pathways are rearranged to return to pre-pregnancy.”
Guintivano and colleagues used three biological assays to detect B-cell variation: RNA sequencing, DNA genotyping, and DNA methylation assessment, all designed to measure cell composition and activity.
In women with PPD, the researchers found thousands of individual B-cell transcripts – coding sequences for protein synthesis – that were not found in women without PPD. These differences have been shown to be due in part to DNA variants and genetic regulation.
A fourth genetic method, called pathway analysis, which links coding sequences to possible physiological pathways that derived proteins interact with, also revealed changes in B-cell activation in women with and without PPD. However, at this stage, it is unclear what exactly is behind these changes and how they may affect the condition.
“This is the largest study of its kind, but we still don’t know why B cells change,” says Guintivano. “Do they reflect other changes in the body that cause or cause PPD? What drives this B-cell behavior?”
It is in this direction that further research should be carried out. Previous research has looked closely at genes and hormones and their association with PPD, but the team says “multiple avenues” need to be explored to fully understand the condition.
What the current study provides is a large and diverse sample size – the largest in the history of research of its kind on postpartum depression – and several possible clues about how the immune system may be a cause and potential remedy for what new mothers experience.
PPD can be devastating for both parents of a child, leading to anxiety, low energy, extreme sadness, eating and sleeping problems, and even suicidal thoughts. The researchers praised the women who took part in the study.
“The women in this study are new mothers who came at a very critical time, when their babies were a few weeks old, to take part in the study and help other women,” says Guintivano.
“I want to thank them for that. We want to make their contributions fair in our research.”
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