Electronic Fetal Monitoring During Premature Labor and the Occurrence of Perinatal Mortality in Very Low Birthweight Infants

ABSTRACT: The efficacy of intrapartum electronic fetal heart rate monitoring (EFM) in reducing perinatal mortality is uncertain. In a multihospital study in King County, Washington, we compared the effect of EFM with periodic auscultation in singleton infants with birthweights of 700 to 1500 g. Charts were reviewed for all 304 such pregnancies delivered during 1977‐1979 at the 14 area hospitals that provide obstetric care. The group with periodic auscultation showed a relatively higher proportion of risk factors for perinatal mortality: extremely low birthweight (< 1100 g), noncephalic presentation, delivery outside a tertiary obstetric center, and absence of premature rupture of membranes. Adjusted for these risk factors, the perinatal mortality of the EFM group was only slightly less than that of the group with periodic auscultation (relative risk = 0.91; 95% confidence limits = 0.65–1.3). Our results suggest that in infants of very low birthweight, the probability of perinatal death is little affected by the choice of EFM or periodic auscultation to monitor fetal heart rate.