Early prenatal exposure to pandemic influenza A (H1N1) infection and child psychomotor development at 6 months - A population-based cohort study.

BACKGROUND: Studies investigating gestational influenza and child neurodevelopment are still scarce, particularly concerning timing of infection in pregnancy. This is the first study to investigate associations between gestational influenza and infant psychomotor development and temperament at 6 months.

METHODS: Data from The Norwegian Influenza Pregnancy Cohort, established during the 2009 swine flu pandemic, were utilized. Information on influenza infection, vaccination, maternal health and child health and development is available from questionnaires, national registry data and maternal blood samples drawn at delivery. Maternal influenza A H1N1 pdm09 infection was serologically confirmed. 609 children with complete data were identified. Children of exposed and non-exposed mothers were compared using generalized linear models.

RESULTS: Children exposed to influenza during gestational weeks (gw) 0-8 had adjusted general development scores indicating slightly delayed development compared to non-exposed children (0.28 standard deviations (SD) 95% confidence interval (CI): -0. 01; 0.58; p = 0.06). The temperamental scores of children exposed during gw 0-8 were slightly higher (0.31 SD; 95% CI: -0. 03; 0.64; p = 0.07) than non-exposed children indicating a more difficult temperament. In comparison, the developmental scores for children exposed in gw 9-40 were -0.31 SD (95% CI: -0. 65; 0.04; p = 0.09) better than non-exposed children, while the temperamental scores were 0.17 (95% CI: -0. 23; 0.56; p = 0.36) for the same period.

CONCLUSION: Modest associations were found between maternal influenza A (H1N1) pdm infection during gestational weeks 0-8 and psychomotor development at 6 months.