Can electronic fetal monitoring identify preterm neonates with cerebral white matter injury?

OBJECTIVE

Although preterm delivery occurs in only 10% of all births, these infants are at high risk for cerebral white matter injury and constitute a third of all cerebral palsy cases. Our objective was to estimate if electronic monitoring can identify preterm fetuses diagnosed with brain injury during the neonatal period.

METHODS

In this case-control study, 150 consecutive neonates with ultrasonography-diagnosed cerebral white matter injury were matched by gestational age within 7 days to 150 controls with normal head ultrasonograms. Tracings were retrieved for 125 cases (83%) and 121 controls (81%) and reviewed by 3 perinatologists blinded to outcome. Vaginal (64 cases, 72 controls) and cesarean deliveries (61 cases, 49 controls) were analyzed separately.

RESULTS

There was no difference in baseline heart rate, tachycardia, bradycardia, short-term variability, accelerations, reactivity, number or types of decelerations, or bradycardic episodes between cases and controls in either the vaginal or cesarean delivery groups. For the 6 neonates with metabolic acidosis severe enough to increase the risk for long-term neurologic morbidity, there was a significant increase in baseline amplitude range less than 5 beats per minute; however, its positive predictive value in predicting severe metabolic acidosis was only 7.7%. Increasing late decelerations were associated with decreasing umbilical arterial pH and base excess, but were not significantly different in the acidosis and control groups (1.0 +/- 1.8, 0.55 +/- 1.23 late decelerations per hour, P = .39).

CONCLUSION

Although decreased short-term variability and increased late decelerations are associated with decreasing umbilical arterial pH and base excess, electronic fetal monitoring is unable to identify preterm neonates with cerebral white matter injury.