Body mass index trajectories up to preschool age in a multi-ethnic population; relations with maternal gestational diabetes, BMI and gestational weight gain.

Aim: Independent effects of gestational diabetes (GDM), maternal prepregnant obesity and gestational weight gain on offspring BMI and obesity are scarcely documented. We examined associations between GDM and children's BMI trajectories from birth to 4-5 years age, and effects of prepregnant obesity and gestational weight gain not mediated through GDM.

Methods: We included 734 children from a population-based, multi-ethnic cohort of women and their offspring followed from early pregnancy. All women were screened for GDM. Using linear mixed models, we explored associations between maternal factors and children's BMI development through seven serial measurements.

Results: At birth and age 4-5 years, BMI of children exposed to GDM was similar to those not exposed. However, they had slower BMI growth (B = -0.1 BMI units/month (95% CI: -0.17, -0.04)) during first 6 months, and faster BMI growth from 6 months to 4-5 years. Maternal prepregnant obesity was associated with higher child BMI at birth, and thereafter persistently higher BMI. High gestational weight gain was associated with faster BMI growth from 6 months to 4-5 years.

Conclusion: Effects of maternal GDM, prepregnant obesity, and gestational weight gain on children's BMI and BMI trajectories from birth to preschool age differed in relation to effect size, timing and direction.