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

Survival of extremely premature infants has been significantly higher in th e last decade than previously, and may well have improved. The majority of infants greater than or equal to 25 weeks' gestation survive today. Surviva l of infants 23 and 24 weeks' gestation is significantly lower, but is by n o means negligible. Reports of survival of infants less than 22 weeks or 50 0-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 kn own. Currently available data do not allow survival of the individual extre mely low-birth weight or extremely premature infant to be predicted with cl inically acceptable accuracy. The concept of a limit of viability is vague and clinically and ethically simplistic. The provision of neonatal intensiv e care is not necessarily beneficial or justified merely because it affords some chance of survival.