Maternal dietary patterns, breastfeeding duration, and their association with child cognitive function and head circumference growth: A prospective mother–child cohort study

Background Early life is a critical period for neurodevelopment, where factors such as maternal nutrition and breastfeeding duration significantly impact the growth of head circumference and cognitive development in children. Our study aimed to explore the associations between maternal dietary patterns during pregnancy, duration of breastfeeding, and their impacts on child head circumference and cognitive outcomes. Methods and findings Our study utilised data from the Copenhagen Prospective Studies on Asthma in Childhood 2010 cohort, which enrolled 700 mother–child pairs between 2008 and 2010 with 86% clinical follow-up at age 10. Pregnancy dietary patterns, described as ‘Varied’ and ‘Western,’ were derived from food frequency questionnaires and used to model quantitative metabolite scores via sparse partial least squares modelling of blood metabolome data. Cognitive development was assessed using the Bayley Scales of Infant Development at 2.5 years and the Wechsler Intelligence Scale for Children at age 10. Head circumference was measured from 20 weeks gestation to 10 years, and calibrated using related anthropometric measures. Growth trajectories were evaluated using linear mixed models and latent class trajectory models. Parental and child genetic influences for cognition and head circumference were controlled by including polygenic risk scores derived from genomic data. We found that a Western dietary pattern during pregnancy was associated with lower cognitive scores at age 2.5 ( β −1.24 [−2.16, −0.32], p = 0.008) and reduced head circumference growth ( p -interaction < 0.0001). We found that a Varied dietary pattern during pregnancy was associated with higher estimated intelligence quotient (IQ) at age 10 ( β 1.29 [0.27, 2.3], p = 0.014). Additionally, head circumference growth was associated with higher cognitive scores at age 10 ( β 3.40 [1.21, 5.60], p = 0.002), and it partly mediates the association between the Varied dietary pattern and estimated IQ (proportion mediated 13.5% [0.01, 0.71], p = 0.034). Extended breastfeeding duration was also independently associated with increased head circumference growth ( p -interaction < 0.0001). These patterns and correlations were consistent even after adjusting for potential confounders and accounting for genetic influences. Conclusions Our findings reveal that a Western dietary pattern during pregnancy is associated with lower cognitive scores at age 2.5 and decreased head circumference growth, suggesting potential adverse impacts on early neurodevelopment. Conversely, a Varied dietary pattern is linked with a higher estimated IQ at age 10, with head circumference growth contributing to this positive outcome. These findings highlight the critical role of maternal nutrition during pregnancy, and duration of breastfeeding, in promoting optimal neurodevelopmental outcomes. Effective public health strategies should therefore focus on enhancing maternal dietary practices to support better cognitive and physical development in children.