Parental Body Mass Index, Gestational Weight Gain, and Risk of Macrosomia: a Population-Based Case-Control Study in China

Background The prevalence of macrosomia has risen markedly worldwide, including in China, during the past two decades. Few epidemiological studies, however, have investigated the risk factors for macrosomia in China. This study was designed to investigate the associations between parental anthropometric characteristics, gestational weight gain (GWG), and risk of macrosomia in China. Methods This population-based, case–control study in Wuhan, China, included a total of 6341 subjects (870 cases and 5471 controls). Multivariable logistic regression was conducted to calculate odds ratios (OR) and 95% confidence intervals (CI). Results Mothers or fathers who were overweight or obese before pregnancy had an elevated risk of giving birth to a macrosomic infant compared with their normal weight counterparts. Women with GWG above the Institute of Medicine (IOM) recommendation had an adjusted OR of 6.09 [95% CI 5.04, 7.35] for delivering a macrosomic infant compared with women who had GWG within the IOM recommendation. When stratified by maternal pre-pregnancy body mass index (BMI), women who were underweight or normal weight before pregnancy were observed to have a higher risk of macrosomia birth associated with greater GWG. Conclusions Parental pre-pregnancy overweight/obesity and excessive GWG during pregnancy were highly associated with macrosomia. The association with GWG was most pronounced in mothers who had a normal or underweight pre-pregnancy BMI. Weight control efforts before pregnancy for mothers and fathers as well as control of maternal gain during pregnancy may reduce the risk of macrosomia.