Breastfeeding, prenatal depression and children's IQ and behaviour: a test of a moderation model

Background: We aimed to determine the associations between breastfeeding and children's neurodevelopment indexed by intelligence quotient (IQ) and emotional and behavioural problems through mid-childhood adjusting for prenatal and postnatal depression and multiple confounders; and to test the novel hypothesis that breastfeeding may moderate the effects of prenatal depression and anxiety on children's neurodevelopment. Methods: The study is based on women and their children from the longitudinal Avon Longitudinal Study of Parents and Children (n=11,096). Children's IQ was derived from standardized in-person testing; behaviour problems were assessed according to parent-report; information on breastfeeding, prenatal depression and anxiety and multiple confounders were derived from self-report questionnaires. We conducted hierarchical multiple regression adjusting for several covariates. Results: 43% women were exclusively breastfeeding at 1 month and an additional 16.8% were engaged in mixed or partial breastfeeding. Both exclusive breastfeeding (B = 2.19; SD = 0.36, p = .00) and mixed feeding (B = 1.59; SD = 0.52; p = .00) were positively associated with IQ at 8 years of age, after adjusting for covariates. Exclusive breastfeeding was negatively associated with hyperactivity/attention deficit at 4 years (B = −.30, SD = .05; p < .01); mixed feeding was related to hyperactivity/attention deficit at age 9 (B = .20; SD = .08; p = .03) after adjustments. There was no association between breastfeeding and emotional or conduct problems. Breastfeeding did not moderate the association between prenatal depression and anxiety and children's neurodevelopment. Conclusions: The selective association between breastfeeding and neurodevelopmental measures suggests a nutritional rather than broader beneficial psychological effect on child neurodevelopment. Breastfeeding did not moderate the associations between prenatal depression and anxiety and child neurodevelopment, suggesting separate mechanisms of action.