Objective: To examine the independent contribution of risk factors developing during pregnancy to subsequent risk of obesity in young children.
Methods: We conducted a historical cohort study using data from electronic medical records of mothers and their 3,302 singleton offspring born between 2004 and 2007 at a community-based obstetric facility who attended a 4-year well visit at a pediatric practice network. The child's body mass index (BMI) z score at age 4 years was studied in relation to the mother's gestational weight gain, gestational diabetes mellitus, gestational hypertension or preeclampsia, and prenatal tobacco use. Institute of Medicine categories defined excess and inadequate gestational weight gain at term. Analysis of variance and multiple linear regression were used to test their independent relation to BMI.
Results: Mothers were white (39%), African American (46%), and of Hispanic ethnicity (11%); 46% were privately insured. The association of net gestational weight gain with the child's BMI z score was significant after adjustment for prepregnancy maternal factors (P<.001); gestational diabetes mellitus, gestational hypertension, and tobacco use were not significant in adjusted models. Children of mothers with excess gestational weight gain had a higher mean BMI z score (P<.001) but a significant association was observed only for inadequate gestational weight gain after adjusting for prepregnancy BMI and other covariates. Prepregnancy BMI (P<.001), Hispanic ethnicity (P<.001), and being married (P<.05) were independently associated with increasing BMI z score of the offspring.
Conclusions: Preconception maternal factors had a greater influence on child obesity than prenatal factors. The gestational weight gain category was independently related to BMI z score of 4 year olds, but this association was significant only for mothers with inadequate gestational weight gain.
Level of evidence: II.