Not all underweight newborn infants are premature; some have been retarded in their intrauterine growth. Prenatal-growth retardation is sometimes genetically determined, and in other instances is related to disturbed placental function which presumably restricts transfer of nutrients to the fetus. Such malnourished (dysmature) neonates are more prone to perinatal death than are wellnourished infants of the same gestational age. However, if born in good condition, dysmature infants have fewer neonatal difficulties than do premature infants of a similar birth weight. They usually do not suffer from respiratory distress and soon begin to gain weight, although their postnatal growth is often relatively subnormal for at least several years.
Dysmature infants also have an increased incidence of mental subnormality. A symptomatic neonatal hypoglycemia which sometimes develops in these infants may contribute to this mental subnormality by damaging the brain.1 Neonatal death may occur during a hypoglycemic episode or from cardiac or