Immune Dysregulation May Drive Long-Term Postpartum Depression

Will Pass

December 13, 2022

Postpartum depression, anxiety, and posttraumatic stress disorder that persist 2-3 years after birth are associated with a dysregulated immune system that is characterized by increased inflammatory signaling, according to investigators.

These findings suggest that mental health screening for women who have given birth should continue beyond the first year postpartum, reported lead author Jennifer M. Nicoloro-SantaBarbara, PhD, of Brigham and Women’s Hospital, Harvard Medical School, Boston, and colleagues.

"Delayed postpartum depression, also known as late-onset postpartum depression, can affect women up to 18 months after delivery," the investigators wrote in the American Journal of Reproductive Immunology. "It can appear even later in some women, depending on the hormonal changes that occur after having a baby (for example, timing of weaning). However, the majority of research on maternal mental health focuses on the first year post birth, leaving a gap in research beyond 12 months postpartum."

To address this gap, the investigators enrolled 33 women who were 2-3 years postpartum. Participants completed self-guided questionnaires on PTSD, depression, and anxiety, and provided blood samples for gene expression analysis.

Sixteen of the 33 women had clinically significant mood disturbances. Compared with the other participants, these 16 women had significant upregulation of genes driving inflammatory pathways and significantly reduced activation of genes associated with viral response.

"The results provide preliminary evidence of a mechanism (e.g., immune dysregulation) that might be contributing to mood disorders and bring us closer to the goal of identifying targetable biomarkers for mood disorders," Nicoloro-SantaBarbara said in a written comment. "This work highlights the need for standardized and continual depression and anxiety screening in ob/gyn. and primary care settings that extends beyond the 6-week maternal visit and possibly beyond the first postpartum year."

Findings Draw Skepticism

"The authors argue that mothers need to be screened for depression/anxiety longer than the first year postpartum, and this is true, but it has nothing to do with their findings," said Jennifer L. Payne, MD, an expert in reproductive psychiatry at the University of Virginia, Charlottesville.

In a written comment, she explained that the cross-sectional design makes it impossible to know whether the mood disturbances were linked with delivery at all.

"It is unclear if the depression/anxiety symptoms began after delivery or not," Payne said. "In addition, it is unclear if the findings are causative or a result of depression/anxiety symptoms (the authors admit this in the limitations section). It is likely that the findings are not specific or even related to having delivered a child, but rather reflect a more general process related to depression/anxiety outside of the postpartum time period."

Only prospective studies can answer these questions, she said.

Nicoloro-SantaBarbara agreed that further research is needed.

"Our findings are exciting, but still need to be replicated in larger samples with diverse women in order to make sure they generalize," she said. "More work is needed to understand why inflammation plays a role in postpartum mental illness for some women and not others."

The study was supported by a Cedars-Sinai Precision Health Grant, the Cousins Center for Psychoneuroimmunology, University of California, Los Angeles, and the National Institute of Mental Health. The investigators and Payne disclosed no relevant conflicts of interest.

This story originally appeared on, part of the Medscape Professional Network.


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