Birth weight and body composition of neonates born to Caucasian compared with African-American mothers.

Abstract

To estimate whether neonates of African-American women have lower birth weights because of either decreased lean body mass or fat mass. A secondary analysis of a cohort of 104 African-American and 274 Caucasian term, singleton, healthy pregnancies. Women with existing or gestational diabetes were excluded. Neonatal body composition was estimated using anthropometric measurements. There were significant differences in maternal age (29.5 compared with 25.8, P<.001), prepregnancy body mass index (26.2 compared with 30.9 kg/m, P<.001), and weight gain during pregnancy (15.2 compared with 13.4 kg, P=.03) in Caucasian compared with African-American women, respectively. After adjusting for these factors, African-American women's neonates had significantly lower birth weights (3.20 compared with 3.36 kg, P=.003), less lean body mass (2.80 compared with 2.94 kg, P=.002), but no difference in fat mass (392 compared with 417 g, P=.078). Decreased birth weight in African-American neonates is due to lower lean body mass and not a difference in adiposity.