The Limit of Viability A Single Regional Unit's Experience

Objective: To establish the limit between beneficial and futile management in the extremely preterm infant, born at the limit of viability, at 22 to 26 weeks of gestationalage(GA). Design: Retrospective study (11-year study period). Setting: A tertiary regional neonatal unit. Participants: Inborn infants (n=841) with a birth weight of 1000 g or less and GA 22 0/7 through 26 6/7 weeks. Intervention: We compared mortality and neurodevelopmental outcome between 2 periods, epoch 1 (January 1998 to June 2003) and epoch 2 (July 2003 to December 2008). For neurodevelopmental data, epoch 2 extended only to December 2006. Main Outcome Measures: We reviewed survival rates and adverse neurodevelopmental outcome rates at 18 to 24 months' corrected age. Results: In the past decade, survival rates continued to increase while neurodevelopmental impairment rates in the extremely preterm infant decreased. From epoch 1 to epoch 2, the increase in survival rate occurred in infants born at 22 weeks' estimated GA, from 20% to 40%, while the decrease in neurodevelopmental impairment (54% to 28%) and severe neurodevelopmental impairment (35% to 8%) occurred in infants born at 23 to 24 weeks' estimated GA. Conclusions: Novel and aggressive neonatal therapies continue to affect neonatal outcome, mainly in infants born at the limit of viability. Our data suggest that each center offer prospective parents an assessment of the limits of viability based on their updated outcome results.