Maternal preconception weight trajectories, pregnancy complications and offspring's childhood physical and cognitive development.

There is limited evidence on the association between maternal preconception body mass index (BMI) trajectories and pregnancy complications and child development. This study examined the relationships of maternal BMI trajectories, diabetes and hypertensive disorders during pregnancy and offspring's childhood physical and cognitive development. Data were from the Australian Longitudinal Study on Women's Health and the Mothers and their Children's Health study (n=771). Women's preconception BMI trajectories were identified using group-based trajectory modelling. Children's physical and cognitive development (up to the average age of 5 years) were obtained from the Ages and Stages Questionnaire (suspected gross motor delay) and the Australian Early Development Census (AEDC). Generalized estimating equation models, adjusted for maternal sociodemographic and lifestyle factors, were used for analyses. Three distinct BMI trajectories were identified (normative, chronically overweight and chronically obese). Children born to chronically obese women were more likely to be classified as developmentally vulnerable/at-risk on AEDC domains; gross and fine motor skills [risk ratio (RR)=1.64, 95% confidence interval (CI): 1.04, 2.61] and communication skills and general knowledge (RR=1.71, 95% CI: 1.09, 2.68). They also had an elevated risk of suspected gross motor delay (RR=2.62, 95% CI: 1.26, 5.44) compared with children born to women with a normative BMI trajectory. Maternal diabetes or hypertensive disorders during pregnancy were not associated with child outcomes. Maternal preconception BMI trajectories were associated with poorer childhood development. This study finding underscores the importance of excessive weight gain prevention throughout the reproductive stage of life.