FACTORS AFFECTING FETAL GROWTH AND BODY-COMPOSITION

OBJECTIVE: Our purpose was to identify factors affecting fetal growth with birth weight and body composition. STUDY DESIGN: A total of 183 s ingleton infants had birth weights and estimates of body composition p erformed within 24 hours of birth. Independent variables included were (1) maternal height, weight, pregravid weight, weight gain, education , and parity, (2) paternal height and weight, and (3) neonatal sex and gestational age. Best-fit stepwise regression analysis was used to co rrelate the independent variables with birth weight, fat-free mass, an d fat mass. RESULTS: Compared with females, males had greater birth we ight (p = 0.009) and fat-free mass (p = 0.0001) but not fat mass (p = 0.32). The strongest predictors were gestational age with birth weight (R(2) = 0.10), neonatal sex with fat-free mass (R(2) = 0.08), and par ity with fat mass (R(2) = 0.08). By use of the significant independent variables we explained 29% of the variation in birth weight, 30% in f at-free mass, and 17% in fat mass. CONCLUSION: These data support the concept that various genetic and environmental factors may modify feta l growth by differentially affecting growth of fetal fat and fat-free mass.