Sibling Analysis Weakens Link Between Pregnancy Flu and Child Neuropsychiatric Disorders
A binational birth cohort initially found a modest link between influenza infection during pregnancy and any neuropsychiatric disorder in children, but the association disappeared in sibling comparisons. Researchers said the population-level findings should not be read as proof that maternal flu directly causes these disorders, and shared familial factors may explain part of the signal. They cautioned that the sibling analyses had smaller samples and wider confidence intervals, so they do not definitively rule out an association.
Researchers examined mother-child pairs with live births from 2010 through 2017 in South Korea and Japan. In ordinary population analyses, maternal flu during pregnancy showed a small statistical link to any child neuropsychiatric diagnosis. When siblings discordant for maternal flu exposure were compared, that link was no longer statistically significant.
The authors say shared family characteristics might account for part of the earlier signal. They also note sibling analyses had fewer participants and broader uncertainty ranges, so they cannot fully exclude a real effect. Existing guidance on preventing and treating flu in pregnancy remains unchanged.
This finding may reassure expectant parents and clinicians who encounter conflicting claims about pregnancy flu and child mental health. It could also encourage researchers to weigh family-level factors when studying maternal infections. Because sibling comparisons were less precise, the study may not settle the question, and public health messaging may continue to emphasize flu prevention in pregnancy without implying that maternal infection directly causes neuropsychiatric disorders.