Umbilical Artery Blood Gas Analyses in Healthy Term Newborn Infants

Oh, Ye Keun; Ji, Ill Woon; Roh, Jae Sook; Jeong, Eun Hwan; Kim, Hak Soon

Abstract

OBJECTIVES
To study the distributions of pH and gas values in umbilical arterial(UA) blood of normal newborns following uncomplicated pregnancies and vaginal births. Methods: In 457 consecutive normal term infants who were born between March 1995 and June 1998, we examined the UA pH and blood gas values obtained immediately following delivery. Maternal inclusion criteria were defined as an uncomplicated singleton pregnancy and a normal full term spontaneous vaginal delivery. And also neonatal inclusion criteria were defined as a normal intrauterine growth appropriate for gestational age without any malformations and Apgar score of 7 or more at both one and five minutes after birth. Umbilical artery blood samples were collected at each birth and were evaluated for pH, carbon dioxide pressure (PaCO2), oxygen pressure (PaO2) and actual bicarbonate. RESULTS: Histogram of UA pH value resemble normal distribution curve. The lowest UA pH was 7.04 and the 10th percentile value was 7.23. The median UA pH was 7.31 and 5% was below 7.20. The lowest UA PaO2 was 4.6mmHg and the 10th percentile value was 11.5mmHg. The highest UA PaCO2 was 67.2mmHg and the 90th percentile value was 56.5mmHg. The lowest bicarbonate value was 13.2mmol/L and the 10th percentile value was 18.4mmol/L. CONCLUSION: The distributions of the UA pH and gas values of the collective of normal newborns were illustrated. None of the UA pH was below 7.0.