Objective: Knowing risk factors at birth for the development of childhood obesity could help to identify children who are in need of early obesity prevention efforts. The objective of this study was to determine whether children whose mothers were obese in early pregnancy were more likely to be obese at 2 to 4 years of age.
Methods: A retrospective cohort study was conducted of 8494 low-income children who were enrolled in the Special Supplemental Nutrition Program for Women, Infants, and Children (WIC) in Ohio and were followed from the first trimester of gestation until 24 to 59 months of age. Measured height and weight data from WIC were linked to birth certificate records for children who were born in the years 1992-1996. Obesity among 2- to 4-year-olds was defined as a body mass index (BMI) > or =95th percentile for age and gender. Mothers were classified as obese (BMI > or =30 kg/m2) or nonobese (BMI <30 kg/m2) on the basis of BMI measured in the first trimester of the child's gestation.
Results: The prevalence of childhood obesity was 9.5%, 12.5%, and 14.8% at 2, 3, and 4 years of age, respectively, and 30.3% of the children had obese mothers. By 4 years of age, 24.1% of children were obese if their mothers had been obese in the first trimester of pregnancy compared with 9.0% of children whose mothers had been of normal weight (BMI 18.5 and <25 kg/m2). After controlling for the birth weight, birth year, and gender of the children plus the mothers' age, race/ethnicity, education level, marital status, parity, weight gain, and smoking during pregnancy, the relative risk of childhood obesity associated with maternal obesity in the first trimester of pregnancy was 2.0 (95% confidence interval [CI]: 1.7-2.3) at 2 years of age, 2.3 (95% CI: 2.0-2.6) at 3 years of age, and 2.3 (95% CI: 2.0-2.6) at 4 years of age.
Conclusion: Among low-income children, maternal obesity in early pregnancy more than doubles the risk of obesity at 2 to 4 years of age. In developing strategies to prevent obesity in preschoolers, special attention should be given to newborns with obese mothers.