Pre-pregnancy overweight status is associated with increased odds of maternal postpartum obesity and infant macrosomia in San Francisco: A life course perspective on county birth certificate data

Overweight tracks over the life course and cycles across generations from mother to offspring. This study used local birth certificate data to describe the extent of overweight tracking and cycling in San Francisco. The analysis included all live births to San Francisco residents in 2010 with recorded weight status (n=8087, 92% of all births). Multivariable logistic regression models were used to estimate the relative odds of pregnancy weight gain in excess of IOM recommendations, maternal postpartum obesity, and infant macrosomia (birthweight≥4000g) associated with pre-pregnancy weight status, controlling for maternal age, race/ethnicity, insurance type (proxy for income), education, smoking, parity, and prenatal care. Before pregnancy, 18.5% and 9.2% of mothers were overweight (BMI: 25.0-29.9) and obese (BMI≥30.0), respectively. During pregnancy, 64.2% of mothers gained excessive weight. After pregnancy, 48.7% and 34.2% of mothers were overweight and obese, respectively; 7.9% of infants were macrosomic. Mothers who were overweight or obese (BMI≥25.0) before pregnancy were 90% more likely to gain excessive weight during pregnancy (OR=1.9, 1.7-2.1) and 60% more likely to have a macrosomic infant (OR=1.6, 95%CI:1.4-2.0) than mothers who were normal weight before pregnancy. 88% of mothers who were overweight but not obese (BMI: 25.0-29.9) before pregnancy were obese after pregnancy, compared to 13% of those who were normal weight before pregnancy (OR=27.5, 95%CI:23.5-32.3). SFDPH-MCAH prioritizes overweight prevention in the preconception period and prenatal care intervention during pregnancy to limit risk magnification over the life course.