The Association Between Maternal Obesity and Fetal Size for Gestational Age in Singletons and Twins
Abstract
Maternal obesity and multiple births have adverse effects on fetal growth; prevalence of both are increasing in Canada. We explored associations between maternal obesity and infant size for gestational age using data from a London perinatal database. Birthweight for gestational age was assessed using standards published by Robertson (2002) to classify Small for Gestational Age (SGA) and Large for Gestational Age (LGA) in 30396 singletons and 1346 twins. Associations were estimated using logistic regression for singletons and the GEE extension of logistic regression for twins. Increased maternal pre-pregnancy BMI was statistically significantly associated with decreased odds of SGA in singletons (p< 0.0001), and increased odds of LGA in singletons and twins (p< 0.0001, p= 0.0004 respectively). Results suggest that maternal BMI may influence size for gestational age differently in singleton and twins.