Fetal Macrosomia: Exploring the Impact of Pre-pregnancy Body Mass Index and Gestational Weight Gain [38L

Abstract

INTRODUCTION: This study was undertaken to evaluate the relationship between pre-pregnancy body mass index (PPBMI), gestational weight gain (GWG) and fetal macrosomia. METHODS: Vital statistics (birth) data collected by the National Center for Health Statistics (NCHS) was utilized. Using the 2015 data, GWG was calculated and the birth cohort consisting of singleton gestations was classified into inadequate, adequate and excess GWG categories under each PPBMI stratum, as per the 2009 Institute of Medicine guidelines. Multivariate logistic regression analyses were used to predict the risk for fetal macrosomia (>4,500 g) in each PPBMI and GWG group while adjusting for age, race/ethnicity, education, marital status, insurance and smoking status. RESULTS: Birth certificate data from 3,618,822 patients were reviewed. In comparison to women with normal PPBMI, overweight (OR 1.87; 95% CI 1.82–1.92) and obese (OR 3.25; 95% CI 3.17–3.33) women had higher odds for fetal macrosomia. Excess GWG significantly increased the risk for fetal macrosomia in women who were underweight (OR 3.55; 95% CI 2.72–4.65), normal weight (OR 3.01; 95% CI 2.96–3.94), overweight (OR 2.66, 95% CI 2.52–2.81) and obese (OR 1.93; 95% CI 1.86–2.01) as compared to respective PPBMI matched cohorts with adequate GWG. Notably, inadequate GWG in overweight (OR 0.56, 95% CI 0.53–0.66) and obese (OR 0.72; 95% CI 0.68–0.76) women showed a risk reduction compared to PPBMI matched controls with adequate GWG. CONCLUSION: Excess GWG, especially in the setting of higher PPBMI predicts an increased risk for fetal macrosomia.