Arteriovenous differences in cord blood gas analysis and the prediction of adverse neonatal outcome

Acta Obstet Gynecol Scand. 2018 Jun;97(6):688-693. doi: 10.1111/aogs.13340. Epub 2018 Mar 30.


Introduction: The aim of this paper was to determine whether arteriovenous differences of pH and pCO2 are useful predictors of adverse neonatal outcome in acidemic neonates.

Material and methods: An established database of 8759 term, singleton, non-anomalous neonates with validated cord gases and outcomes [Encephalopathy (Grade 2/3), Apgar <7 at five minutes and composite neonatal outcomes of neurological and systemic involvement] was used. Analysis was of the cohort of the 520 acidemic (arterial pH <7.10) neonates. Chi-square tests with odds ratio (OR), 95% CI were calculated for dichotomous cut-offs of differences; hierarchical logistic regression was used to examine the predictive performance over and above arterial pH.

Results: Arteriovenous hydrogen ion concentration ([H+ ion]) differences do not predict neonatal outcomes except low Apgar scores, and large pCO2 differences are associated with worse neonatal outcomes. Nevertheless, neonates with large arteriovenous [H+ ion] and pCO2 differences have lower arterial pH values. Hierarchical regression demonstrates that arteriovenous pCO2 differences do not add predictive value beyond arterial pH and arteriovenous [H+ ion] adds only to the prediction of low Apgar scores.

Conclusions: Arteriovenous differences of [H+ ion] and pCO2 are not useful independent predictors of adverse neonatal outcomes in acidemic neonates.

Keywords: Arterial cord pH; arteriovenous pCO2 difference; arteriovenous pH difference; cord gases; neonatal outcomes.

Publication types

  • Observational Study

MeSH terms

  • Acidosis / blood*
  • Adult
  • Blood Gas Analysis*
  • Female
  • Fetal Blood
  • Humans
  • Hydrogen-Ion Concentration
  • Infant, Newborn
  • Neonatal Screening / methods*
  • Predictive Value of Tests
  • Pregnancy
  • Pregnancy Outcome*
  • Umbilical Arteries