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

Abstract

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 mor- tality 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 cer- tainty 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.