Background: Maternal metabolic disturbances and diet may influence long-term infantile neurodevelopment. We investigated whether maternal gestational diabetes mellitus (GDM), obesity, and diet could affect the neurodevelopment of 2-year-old children.

Methods: Neurodevelopment of children (n = 243) born to mothers with overweight or obesity was assessed with the Bayley Scales of Infant and Toddler Development-Third Edition, and the Hammersmith Infant Neurological Examination. Maternal adiposity was determined by air displacement plethysmography, and GDM with an oral glucose tolerance test. Dietary assessment included diet quality and fish consumption questionnaires, and three-day food diaries, from which dietary inflammatory index (DII (R)) scores were computed.

Results: GDM was associated with weaker expressive language skills (adj.beta = -1.12, 95% CI = -2.10;-0.15), and higher maternal adiposity with weaker cognitive, language, and motor skills in children (adj.p < 0.05). Maternal good dietary quality (adj.beta = 0.87, 95% CI = 0.004;1.73) and higher fish consumption (adj.p = 0.02) were related to better expressive language skills. DII scores were not associated with children's neurodevelopment.

Conclusions: Findings suggest that GDM and higher maternal adiposity may lead to weaker neurodevelopmental skills, although still within the mean normative range in this population of children. Good dietary quality and higher fish consumption during pregnancy could benefit a child's language development.