Correlation of commonly used measures of intrauterine growth with estimated neonatal body fat.

Several morphometric measures have been used to identify infants at greatest risk from aberrant intrauterine growth. 119 near-term infants were studied to answer the more basic question of how well measures, such as birthweight percentile, ponderal index, the body mass index and the weight/length ratio reflect body fat in the neonate. Skinfold thicknesses were measured as an estimate of fat stores. Multiple regression analysis revealed that the weight/length ratio showed the strongest correlation with relative adiposity, explaining 52% of the variance. Further, sequential exponentiation of the crown-heel length in body mass index and ponderal index decreased the correlation with estimates of body fat. The simple weight/length ratio, exhibiting both a close correlation with body fat and independence of gestational age, race and sex, in near-term infants may be the best morphometric measure of the nutritional component of intrauterine growth in the neonate.