Evaluation methods for intrauterine growth using neonatal fat stores instead of birth weight as outcome measures: fetal and neonatal measurements correlated with neonatal skinfold thicknesses.

Neonatal anthropometry, including timed skinfold measurements, was performed on 55 products of selected pregnancies. These skinfold measurements were compared with published standards of measurements obtained by similar techniques. Values outside the 3rd percentile to 97th percentile range were overlaid on the birth weight/menstrual age relationship of these subjects. Seven of 10 subjects with the lowest midtriceps skinfolds weighed more than 2500 g at birth (2 more than 3500 g) and 2 of 4 with the largest midtriceps skinfold had birth weights less than 4000 g. This comparison emphasizes the imprecision of birth weight as a measure of quality of fetal growth. Since skinfold thickness measurement is cumbersome for clinical use, other neonatal measures that may be more readily available to the clinician were examined for correlation with skinfolds. Simple birth weight/crown-heel length ratio was found to have the closest relationship of the parameters examined. Although estimated fetal weight was found to be the ultrasonography-derived parameter best correlated with skinfold thickness, ultrasonography discriminated poorly between babies with normal and low skinfolds. Low skinfold thickness predicted thermal vulnerability in the nursery better than did birth weight.