Hypoxia with acidosis in extremely preterm born infants was not associated with an increased risk of death or impaired neurodevelopmental outcome at 6.5 years.

<bold>Aim: </bold>It is not clear whether perinatal acidosis can predict poor outcomes in extremely preterm infants and we investigated associations between intrapartum hypoxia and mortality and neurodevelopmental outcomes.<bold>Methods: </bold>We used nationwide data on 705 infants from the Extremely Preterm Infants in Sweden Study, delivered at 22-26 weeks of gestation during 2004-2007. Comprehensive neurodevelopmental assessments were performed on survivors at 2.5 (n = 456) and 6.5 (n = 441) years of corrected age. Gestational age-related changes in umbilical cord arterial pH were compared with reference values for term newborn infants, and base excess was also calculated. Associations between low blood gas values (<10th percentile) and mortality and neurodevelopmental outcome were estimated.<bold>Results: </bold>Cord blood determination was more common in surviving infants (P < .001), with pH determined in 322/705 (46%) and base excess in 311/705 (44%). Extremely preterm infants had higher pH values than term infants (P < .0001), with no change from 22 to 26 weeks of gestation (P = .61, r2  = .001). Multiple logistic regression showed no association between low blood gas values and risk of death or neurodevelopmental impairment at 6.5 years (P ≥ .17).<bold>Conclusion: </bold>Hypoxia with acidosis at birth was not associated with an increased risk of death or impaired neurodevelopmental in extremely preterm born children at 6.5 years. [ABSTRACT FROM AUTHOR]