Association of maternal smoking with body composition of the newborn.

The relationship of maternal cigarette smoking to anthropometric measurements of the newborn was investigated in 285 full-term Caucasian infants. Mothers were classified as "smokers" if they reported smoking both before and during the pregnancy (n = 109) and "nonsmokers" (n = 176). Infants of smoking mothers were significantly lighter, shorter, and had smaller head circumferences, and arm circumferences than those of nonsmokers, consistent with previous findings of other investigators. Ponderal index was not different in the two groups. There was no difference between the two groups in any of the skinfold measurements or in calculated cross-sectional fat area of the upper arm. Multiple regression analyses revealed independent effects of smoking on weight, length, and arm circumference, but no independent effect of smoking on any index of subcutaneous fat. These data suggest that the reduction in birth weight in infants whose mothers who smoke is primarily due to reduction in lean body mass of the newborn while deposition of subcutaneous fat is relatively unaffected.