Women with autoimmune disease are more likely to have perinatal depression (PND), according to findings from a new study that also suggested the reverse relationship is true: Women with a history of PND have a higher risk of developing autoimmune disease.
The research, published online on January 9, 2024, in Molecular Psychiatry, was led by Emma Bränn, PhD, Institute of Environmental Medicine, Karolinska Institute, Stockholm, Sweden.
The researchers used data from the Swedish Medical Birth Register and identified all women who had given birth in Sweden between 2001 and 2013. Out of the group of approximately 815,000 women and 1.3 million pregnancies, just more than 55,000 women had been diagnosed with depression during their pregnancy or within a year after delivery.
The researchers then compared the incidence of 41 autoimmune diseases in women who had and did not have PND. They controlled for factors including genetic makeup and childhood environment.
Results indicated that women with autoimmune disease were 30% more likely to have PND (odds ratio, 1.30; 95% CI, 1.25-1.35). Conversely, women with PND were 30% more likely than women with no PND to develop an autoimmune disease (hazard ratio, 1.30; 95% CI, 1.25-1.36).
A sibling comparison helped confirm the results by controlling for some shared genetic and early life environmental factors related to the household in which sisters grew up.
Potential Shared Biological Mechanisms
The association was independent of psychiatric comorbidities, suggesting there may be shared biological mechanisms.
Dr. Bränn told this news organization that the research team wanted to do the study because previous research has shown involvement of the immune system in depression, with similarities in both the symptoms of immune system–activated diseases and depression and the molecular pathways activated by the immune system.
“Adding on top of the tremendous changes in the immune system that we see in the body of the woman during the perinatal period, we hypothesized that autoimmune diseases could be associated to perinatal depression,” she said. “This had also been shown in some previous literature but not to the extent as what we have investigated in this paper.”
She said their results help make a case for counseling women at several points in healthcare interactions — before and after conception and childbirth — and in rheumatology visits to inform women with autoimmune diseases who are contemplating motherhood of the association with developing PND. The results may also demonstrate a need for monitoring women in these groups for depression or autoimmune disease.
Fred Miller, MD, PhD, retired Scientist Emeritus of the Environmental Autoimmunity Group at the National Institute of Environmental Health Sciences, who was not part of the study, said the results seem plausible as they build on early work that demonstrated selected associations between autoimmune conditions and mental illness.
“These associations may be the result of shared genetic and environmental risk factors, including stress, hormonal changes, medications, and the proinflammatory states that can lead to both,” he said.
The novelty, he said, is in the relatively strong associations of PND with autoimmune disease overall and with specific autoimmune diseases.
Strong Link Found With Multiple Sclerosis (MS)
According to the paper, a significant positive bidirectional link was found for autoimmune thyroid disease, psoriasis, MS, ulcerative colitis, and celiac disease.
Researchers found a particularly strong association — double the risk in both directions — between PND and MS.
Dr. Miller said though it is unclear from this study why the association of PND with MS was stronger than with other autoimmune diseases, people with MS are known to be at a high risk for depression in general. That may come from greater shared genetic and environmental risk factors, he added.
Additionally, MS is one of the more common autoimmune diseases, he noted, so the population is larger for study.
He said he was surprised the researchers didn’t investigate medication use because medications used in depression have immunologic effects and medications used in autoimmune diseases could have effects on mental conditions.
The study has implications for clinicians in a wide variety of specialties, Dr. Miller noted.
“It suggests that caregivers be more alert to the signs of developing autoimmune disease in women with perinatal depression and to the signs of developing perinatal depression in those with autoimmune disease,” Dr. Miller said, “so that appropriate screening, diagnostics, and interventions may be undertaken.”
The researchers say they will continue to examine the long-term effects of depression during pregnancy and in the year after childbirth.
“Depression during this sensitive period can have serious consequences for both the mother and the baby,” Dr. Bränn said. “We hope that our results will help decision-makers to steer funding toward maternal healthcare so that more women can get help and support in time.”
The study was financed by Karolinska Institute, Forte (the Swedish Research Council for Health, Working Life and Welfare), the Swedish Research Council, and the Icelandic Research Fund.
The researchers and Dr. Miller reported no relevant financial relationships.
A version of this article appeared on Medscape.com.