[Mortality by birth weight and survival by gestational age and route of delivery in premature infants].

Specific mortality rates for birthweight (BW) and survival for gestational age were determined in babies under 1500 g and less than 34 weeks gestational age (GA), which were born in a private hospital at Santiago, Chile, between 1983 and 1988. Mortality rates were 875/1,000 in babies under 750 g, 391/1,000 for BW between 750 and 999 g, 185/1,000 for BW 1,000 to 1,249 g, and 125/1,000 in newborns who weighed 1,250 to 1,499 g. Survival increased with gestational age from 39% under 26 weeks to 57% at 26 and 27 weeks, reaching 83% at 28 and 29 weeks, 90% at 30 and 31 and 87% at 32 and 33 weeks. No significant difference was found neither in mortality nor in intracranial hemorrhage (ICH) incidence between newborns delivered by cesarean section or vaginal way. Survival of babies born after 26 weeks GA and weighing over 750 g was comparable with that reported by others. The type of delivery is not likely to play a role by itself in mortality or in incidence of severe ICH.