Umbilical Artery Blood Acid-Base and Blood Gas Status Following Uncomplicated Term Vaginal Deliveries in Japanese Newborn Infants.

Abstract

The objective of this study is to define normal values for umbilical artery blood acid-base and blood gas analysis in Japanese newborn infants. Subjects were 236 newborns, who were born after uncomplicated vaginal deliveries at 37 to 42 weeks' gestation. All had a normal finding of fetal heart rate monitoring and were born to women without pregnancy complications such as preeclampsia, fetal growth retardation, diabetes mellitus, twins and meconium-stained amniotic fluid. Specimens were obtained from the umbilical artery as soon after delivery as possible. One to two millilitres of blood were collected. Blood acid-base and gas determinations were performed within five minutes of delivery using a Corning 238 analyzer (Corning Medical, USA). The results of the study for the parameters were : pH, 7.31±0.05 ; pCO2, 39.7±8.0mmHg ; pO2, 21.0±5.8mmHg ; bicarbonate, 20.1±3.1mmol/L ; BE, -5.2±2.8mmol/L(mean value ± 1SD). In conclusion, normal values for umbilical artery blood analysis in a sizable group of Japanese newborns were defined. Umbilical cord blood analysis could provide the most accurate method of quantifying the newborn's acid-base status at delivery and of evaluating obstetric techniques for the management of labour. However, the cut-off value for pathologic fetal acidemia remains to be defined.