Umbilical arterial blood pH: correlation with Apgar score, relevant perinatal factors and effects on short-term neonatal outcomes / 中华围产医学杂志

ABSTRACT

Objective:To investigate the relationship of umbilical arterial blood pH with Apgar score and its perinatal influencing factors as well as effects on short-term neonatal outcomes.Methods:This study retrospectively collected the clinical data of 7 183 singleton newborns who were born at ≥35 gestational weeks with umbilical artery blood gas analysis in Peking University Third Hospital from January 2017 to February 2019. All cases were divided into two groups according to their Apgar scores at 1 min low Apgar group (≤7 scores, n=42) and normal Apgar group (>7 scores, n=7 141). Moreover, according to the pH value of umbilical artery blood they were also allocated into acidosis group (pH<7.2, n=379 ) and normal pH group (pH≥7.2, n=6 804). Independent sample t test, Chi-square test, Fisher's exact test, Pearson's correlation analysis and multivariate logistic regression analysis were used to analyze the correlation between umbilical arterial blood pH and Apgar score, effects of perinatal complications on umbilical arterial blood pH, and influences of acidosis on early neonatal outcomes. Results:The umbilical arterial blood pH in the low Apgar group was significantly lower than that in the normal Apgar group (7.19±0.13 vs 7.32±0.07, t=-6.011, P<0.001). There was a positive correlation between the umbilical arterial blood pH and Apgar score at 1 min ( r=0.217, P<0.001). Fetal distress was an independent risk factor for low Apgar score ( OR=20.553, 95% CI 4.380-96.443, P<0.001). Premature rupture of membranes was an independent risk factor for acidosis ( OR=1.316, 95% CI 1.035-1.673, P=0.025). The incidence of low Apgar score [6.33% (24/379) vs 0.26% (18/6 804), χ2=217.075], respiratory distress [6.60% (25/379) vs 2.62% (178/6 804), χ2=21.205] and intracranial hemorrhage [1.06% (4/379) vs 0.04% (3/6 804), Fisher's exact test] was significantly higher in the acidosis group than in the normal pH group (all P<0.001). Conclusions:Neonates with lower umbilical arterial blood pH value should be closely monitored after birth as they are more likely to have respiratory distress and intracranial hemorrhage. Umbilical arterial blood pH value may be effective and is recommended in predicting neonatal early outcome.