Central Adiposity and Other Anthropometric Factors in Relation to Risk of Macrosomia in an African American population

Previous studies have consistently identified maternal obesity and gestational weight gain as risk factors for macrosomia, but little is known about the effects of central adiposity and body fat distribution. Using self-reported data from the Black Women's Health Study (BWHS), a large follow-up study of U.S. black women, we examined the risk of macrosomia in relation to prepregnancy waist circumference, prepregnancy waist-to-hip ratio, prepregnancy body mass index (BMI), and gestational weight gain. During 1995–2003, BWHS participants ages 21 to 44 years delivered 6,687 full-term singleton births (gestational age >37 weeks). We compared mothers of 691 infants weighing ≥4000g with mothers of 5,996 infants weighing <4000g. Generalized estimating equation models that accounted for more than one birth per mother were used to estimate multivariable odds ratios (OR) and 95% confidence intervals (CI). Independent of prepregnancy BMI, prepregnancy waist circumference was positively associated with risk of macrosomia (OR=1.58, 95% CI 1.07–2.32, for ≥35.0 vs. <27.0 inches (≥88.9 vs. <68.6 cm); P-trend= 0.04). As expected, prepregnancy BMI was also positively associated with macrosomia (OR=1.74, 95% CI 1.25–2.41 for BMI ≥35.0 vs. 18.5–24.9 kg/m(2)). Gestational weight gain above the amount recommended by the 2009 Institute of Medicine report was associated with an increased risk of macrosomia and the association was present in each category of prepregnancy BMI (18.5–24.9, 25.0–29.9, and ≥30.0 kg/m(2); P-trend<0.001). Our data suggest that overall obesity, high gestational weight gain, and high waist circumference are independent risk factors for macrosomia among U.S. black women.