Umbilical cord blood acid–base analysis at birth and long‐term neurodevelopmental outcomes in children: a systematic review and meta‐analysis

Background: Umbilical cord blood acid- base sampling is routinely performed at many hospitals. Recent studies have questioned this practice and the association of acidosis with cerebral palsy.Objective: To investigate the associations between the results of umbilical cord blood acid- base analysis at birth and long -term neurodevelopmental outcomes and mortality in children.Search strategy: We searched six databases using the search strategy: umbilical cord AND outcomes. Selection criteria: Randomised controlled trials, cohorts and case- control studies from high-income countries that investigated the association between umbilical cord blood analysis and neurodevelopmental outcomes and mortality from 1 year after birth in children born at term.Data collection and analysis: We critically assessed the included studies, extracted data and conducted meta-analyses comparing adverse outcomes between children with and without acidosis, and the mean proportions of adverse outcomes. The certainty of evidence was assessed using the Grading of Recommendations, Assessment, Development and Evaluations approach.Main results: We have very low confidence in the following findings: acidosis was associated with higher cognitive development scores compared with non-acidosis (mean difference 5.18, 95% CI 0.84- 9.52; n = two studies). Children with acidosis also showed a tendency towards higher risk of death (relative risk [RR] 5.72, 95% CI 0.90-36.27; n = four studies) and CP (RR 3.40, 95% CI 0.86- 13.39; n = four studies), although this was not statistically significant. The proportion of children with CP was 2.39/1000 across the studies, assessed as high certainty evidence.Conclusion: Due to low certainty of evidence, the associations between umbilical cord blood gas analysis at delivery and long -term neurodevelopmental outcomes in children remains unclear.