History in Siblings May Indicate Risk of Postpartum Psychosis

—
However, the absolute risk for women with an affected sibling was relatively low, at 1.6%

by
Ed Susman, Contributing Writer, MedPage Today
May 20, 2025 • 3 min read

LOS ANGELES — Pregnant women have a higher risk of postpartum psychosis if their sisters had the same condition, a Swedish cohort study suggested.

The relative recurrence risk of postpartum psychosis for siblings adjusted for birth year was 10.34 (95% CI 6.58-16.20, P<0.001), indicating that a woman is over 10 times more likely to develop postpartum psychosis if her sister had the condition compared with a woman whose sister did not have the condition, reported Veerle Bergink, MD, PhD, of the Icahn School of Medicine at Mount Sinai in New York City, during a press briefing at the American Psychiatric Association annual meeting.

In addition, the relative recurrence risk of postpartum psychosis in full siblings was 10.69 (95% CI 6.60-16.26, P<0.001) when adjusted for year of and age at childbirth.

“Despite the higher familial risk of postpartum psychosis among full siblings, the absolute risk for women with an affected sibling was relatively low, estimated at 1.60% within the entire population,” Bergink and colleagues wrote in the American Journal of Psychiatry, where the study was published.

“Our results provide guidance for clinicians working with pregnant women with personal or family histories of postpartum psychosis,” they concluded. “Our findings suggest that female siblings of women who have experienced postpartum psychosis should be counseled that their own risk is elevated, but that the absolute risk for the disorder remains small.”

However, even with the low absolute risk, Bergink said she personally lost a colleague who experienced postpartum psychosis in an event that also took the life of the woman’s 4-month-old baby.

“Postpartum psychosis is one of the most severe psychiatric conditions, with increased risks of suicide and infanticide if untreated, and should thus be addressed as a medical emergency,” the authors noted.

The onset of postpartum psychosis most often occurs within the first month post-delivery. Onset is rapid, and presentation is fluctuating, marked by mood symptoms (mania and depression), psychotic symptoms, cognitive disorganization and confusion, severe anxiety, and sleep problems, the authors explained.

Bergink told MedPage Today that mental health among pregnant women is not routinely addressed in pre- and postnatal care, “but it should be.”

Treatment of postpartum psychosis is available, and antidepressants can work well, she added.

Misty Richards, MD, of the University of California Los Angeles, stressed that “postpartum psychosis is an absolute emergency.”

“As a clinician, we have to catch this early because things can go wildly out of control in the postpartum period,” she said.

For this study, Bergink and colleagues included 1,648,759 women from the Swedish nationwide registries (mean age at childbirth 29.3). Of that group, 2,514 (0.15%) experienced postpartum psychosis within 3 months of their first childbirth.

The researchers then identified 876,084 full sisters (mean age at childbirth 29), and found that 1,154 had a diagnosis of postpartum psychosis.

Bergink said she and her team also looked at female first cousins, finding 461,026 women (mean age at childbirth 27.4), 1,234 of whom had postpartum psychosis. Although cousins showed an elevated relative recurrence risk, these results did not reach statistical significance (relative recurrence risk 1.78, 95% CI 0.70-3.62).