Etiology and outcome of low birth weight and preterm infants.

A population of 489 low birth weight infants was studied to identify specific subgroups with high neonatal morbidity and mortality. It was found that 134 (27.4%) of these infants were born at term but were small for gestational age. The other 355 were preterm and contributed most of the mortality and morbidity of the overall population. There was no significant difference in morbidity and mortality between preterm small and appropriate for gestational age infants. The etiologic analyses show that premature rupture of the fetal membranes and maternal-fetal problems are more frequent causes of low birth weight than preterm labor and that they cause significantly more severe neonatal morbidity. It is concluded that only by developing means to improve the outcome of patients with premature rupture of the membranes and maternal-fetal problems will it be possible to decrease significantly the unacceptably high mortality and morbidity of low birth weight infants.