Mortality and morbidity in extremely preterm infants (22 to 26 weeks of gestation): Austria 1999-2001.

Objective: The aim of this retrospective study was to analyze the mortality and morbidity for extremely preterm infants with a gestational age from 22 to 26 weeks. All infants were born in Austria during the years 1999-2001.

Methods: Data were collected from 16 neonatal intensive care units in Austria. Main outcome criteria were mortality, the rates of chronic lung disease (CLD) and severe retinopathy of prematurity (ROP, stage > or =3) to determine the short-term outcome; the rate of cerebral palsy (CP) at the corrected age of twelve months to assess the long-term outcome.

Results: Overall, 796 preterm infants with a gestational age less than 27 weeks were born in Austria and 581 (73%) were registered as live-born infants. Of those live born, 508 (87%) were analyzed. The mortality rates were 83%, 76%, 43%, 26% and 13% for 22, 23, 24, 25 and 26 weeks' gestation, respectively. The rates of CLD were 33% (22 weeks), 36% (23 weeks), 42% (24 weeks), 31% (25 weeks) and 22% (26 weeks). The rates of ROP of stage > or =3 were 0% (22 weeks), 29% (23 weeks), 23% (24 weeks), 18% (25 weeks) and 10% (26 weeks). The rates of CP at the corrected age of 12 months were 33%, 50%, 33%, 26% and 25% for 22, 23, 24, 25 and 26 weeks' gestation, respectively.

Conclusions: The results of this national study are in accordance with the international literature: mortality and morbidity increased with decreasing gestational age.