Analysis of cry features in newborns with differential fetal growth.

This article describes the relation between neonatal cry features and anthropometric indices of fetal growth. Ponderal indices were calculated to characterize 57 2-day-old infants as underweight for length, average weight for length, or overweight for length. Although no differences were found between the cry features of underweight and overweight infants, these infants at the extremes of the distribution of ponderal indices required more stimulation to elicit a pain cry and had a longer latency from the stimulus to cry onset and a higher fundamental frequency in the cry sound than infants with average ponderal indices. Whereas overweight infants cried for shorter amounts of time than average-weight infants, no differences were found in this sample between the underweight and average-weight infants. Test of differences in the variances of the groups paralleled the tests of mean differences. Because these cry features have been used to distinguish infants along a wide continuum of conditions where the functioning of an infant's central nervous system has been impaired or stressed, it was suggested that certain cry features may reflect the risk status of individual infants with anthropometric signs of both retarded and accelerated fetal growth.