Umbilical artery blood acid-base analysis and fetal heart rate baseline in the second stage of labor.
OBJECTIVE
To evaluate the correlation between umbilical arterial acidemia and second-stage baseline fetal heart rate (FHR) abnormalities in Japanese newborn infants.


METHODS
Subjects were 365 newborns, born at term. Specimens were obtained from the umbilical artery as soon as possible after delivery and blood gas determinations were performed within 5 minutes of delivery. FHR monitoring was performed in the second stage.


RESULTS
Umbilical arterial acidemia occurred in 54.1% of the newborns with moderate to severe bradycardia, in 27.3% with mild bradycardia, and in 19.3% with tachycardia, compared with only 1.3% of those with a normal FHR (p < 0.001). The mean umbilical arterial base excess was significantly greater in newborns with metabolic acidemia (-13.9+/-2.9 mmol/l) than in those with either mixed (-11.5+/-2.8 mmol/l) (p < 0.02) or respiratory (-9.1+/-3.2 mmol/l) (p < 0.01) acidemia.


CONCLUSIONS
The second-stage baseline FHR abnormalities were highly correlated with an increased risk of umbilical arterial acidemia at delivery.
Honjo
S
S
Department of Obstetrics and Gynecology, Gunma University School of Medicine, Japan.
Yamaguchi
M
M
D000138:Acidosis / Q000503:physiopathology*; D001034:Apgar Score; D001784:Blood Gas Analysis; D005260:Female; D006340:Heart Rate, Fetal / Q000502:physiology*; D006801:Humans; D006863:Hydrogen-Ion Concentration; D007231:Infant, Newborn; D007748:Labor Stage, Second / Q000502:physiology*; D011247:Pregnancy; D014469:Umbilical Arteries / Q000737:chemistry*