Intrapartum electronic fetal heart rate monitoring and the identification of metabolic acidosis and hypoxic-ischemic encephalopathy.
OBJECTIVE
The purpose of this study was to determine whether electronic fetal monitoring can identify fetuses with metabolic acidosis and hypoxic-ischemic encephalopathy.


METHODS
The cases were 107 nonanomalous chromosomally normal fetuses with an umbilical arterial pH < 7.0 and base excess < or = 12 mmol/L. Controls were the subsequent delivery that was matched by gestational age and mode of delivery. The last hour of electronic fetal monitoring before delivery was evaluated by 3 obstetricians who were blinded to outcome.


RESULTS
Cases had a significant increase in late and prolonged decelerations/hour and late decelerations/contractions. Those fetuses with hypoxic-ischemic encephalopathy had significant increases in bradycardia, decreased variability, and nonreactivity but no difference in late or variable decelerations/hour. For the identification of hypoxic-ischemic encephalopathy, the sensitivity, specificity, and positive and negative predictive values were 15.4%, 98.9%, 66.7%, and 89.4%, respectively, for bradycardia; 53.8%, 79.8%, 26.9%, and 92.6%, respectively, for decreased variability; 92.3%, 61.7%, 2.7%, and 82.9%, respectively, for nonreactivity; and 7.7%, 98.9%, 50.0%, and 88.6%, respectively, for all 3 abnormalities combined.


CONCLUSIONS
Fetal metabolic acidosis and hypoxic-ischemic encephalopathy are associated with significant increases in electronic fetal monitoring abnormalities, but their predictive ability to identify these conditions is low.
Larma
Joel D
JD
Division of Maternal-Fetal Medicine, Department of Gynecology and Obstetrics, Johns Hopkins University School of Medicine, Baltimore, MD, USA.
Silva
Anadir M
AM
Holcroft
Cynthia J
CJ
Thompson
Richard E
RE
Donohue
Pamela K
PK
Graham
Ernest M
EM
D000138:Acidosis / Q000175:diagnosis*; D000328:Adult; D001784:Blood Gas Analysis; D015148:Cardiotocography / Q000295:instrumentation*; D016022:Case-Control Studies; D005260:Female; D005312:Fetal Blood / Q000737:chemistry; D005865:Gestational Age; D006340:Heart Rate, Fetal / Q000502:physiology; D006801:Humans; D020925:Hypoxia-Ischemia, Brain / Q000175:diagnosis*; D007231:Infant, Newborn; D010100:Oxygen / Q000097:blood; D011237:Predictive Value of Tests; D011247:Pregnancy; D012680:Sensitivity and Specificity; D016037:Single-Blind Method; D014469:Umbilical Arteries