Survival of the extremely preterm infant in North America in the 1990s

Survival of extremely premature infants has been significantly higher in the last decade than previously, and may well have improved. The majority of infants greater than or equal to 25 weeks' gestation survive today. Survival of infants 23 and 24 weeks' gestation is significantly lower, but is by no means negligible. Reports of survival of infants less than 22 weeks or 500-g birth weight are not unique. Moreover, the maximum survival of infants less than or equal to 25 weeks with current state-of-the-art care is not known. Currently available data do not allow survival of the individual extremely low-birth weight or extremely premature infant to be predicted with clinically acceptable accuracy. The concept of a limit of viability is vague and clinically and ethically simplistic. The provision of neonatal intensive care is not necessarily beneficial or justified merely because it affords some chance of survival.