Retarded fetal growth patterns and early neonatal mortality in a Mexico City population.

The study reported here classified 9,660 newborn infants delivered at a maternal and child health center in Mexico City by length of gestation, presence or absence of growth retardation, and (in the case of growth-retarded infants) proportionate or disproportionate growth retardation in terms of the infants' weight and length. It was found that preterm infants (delivered before 38 weeks of gestation) had nine times the early neonatal mortality of term infants, irrespective of growth retardation patterns. Also, the type of fetal growth retardation involved (proportionate or disproportionate) in those cases where such retardation was present was found to have an impact on early neonatal mortality. That is, preterm and term infants classified as having proportionate growth retardation respectively exhibited 1.5 and 9.5 times the early neonatal mortality of preterm and term infants with disproportionate growth retardation. Among other things, these findings suggest a need for assessing types of growth retardation as well as etiologic factors when evaluating mortality risk in newborns.