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.

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.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.

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).

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.