Early Growth and Cognitive Development in Children Born Preterm: Relevance of Maternal Body Mass Index.

OBJECTIVE  Maternal pre-pregnancy body mass index (BMI) represents a surrogate marker of fetal exposures to the maternal metabolism during pregnancy. Yet, it remains poorly understood whether this marker indicates risk of altered trajectories in postnatal growth and development in children born preterm. This study aimed to determine whether maternal pre-pregnancy BMI is associated with altered growth and development in children born preterm. STUDY DESIGN  A retrospective cohort study evaluated pre-pregnancy BMI as the exposure for childhood outcomes using linear regression and mixed effects models. The 38 children included in this follow-up evaluation originally participated in a prospective, observational cohort study to determine longitudinal levels of lipid species in preterm human milk expressed by women who delivered prior to 32 weeks. Childhood outcomes in this study were anthropometric measures during hospitalization (n = 38), after discharge through 36 months (n = 34) and Bayley-III developmental scores through 18 months corrected age (n = 26). RESULTS  In 38 children born prior to 32 weeks, higher maternal pre-pregnancy BMI was independently associated with higher preterm infant growth velocity during hospitalization, but not associated with in-hospital change in length or head circumference and/or postdischarge growth. In univariate linear regression models, higher maternal BMI was associated with lower cognitive scores at 18 months corrected age. This significant association remained in an adjusted model accounting for relevant influences on early childhood development. CONCLUSION  Increasing maternal pre-pregnancy BMI may reflect risk of altered growth and cognitive development in children born preterm. KEY POINTS · Maternal BMI was associated with early preterm infant weight gain.. · Maternal BMI was not associated with postdischarge growth.. · Increased maternal BMI may be associated with lower cognitive function scores in offspring..