Electronic Fetal Monitoring in the United States: Temporal Trends and Adverse Perinatal Outcomes

OBJECTIVE:: To examine trends in electronic fetal monitoring (EFM) use and quantify the extent to which such trends are associated with changes in rates of primary cesarean delivery and neonatal morbidity and mortality. METHODS:: We carried out a retrospective study of more than 55 million nonanomalous singleton live births (24-44 weeks of gestation) delivered in the United States between 1990 and 2004. Changes in the risks of neonatal mortality, cesarean delivery, and operative vaginal delivery for fetal distress, 5-minute Apgar score lower than 4, and neonatal seizures (at 34 weeks of gestation or after) were examined in relation to changes in EFM use. RESULTS:: Electronic fetal monitoring use increased from 73.4% in 1990 to 85.7% in 2004, a relative increase of 17% (95% confidence interval 16-18%). This increase was associated with an additional 5% and 2% decline in early and late neonatal deaths, respectively, at 24-33 weeks of gestation as well as a 4-7% additional decline in the 5-minute Apgar score lower than 4 at 24-33, 34-36, and 37-44 weeks of gestation. Increasing EFM use was associated with a 2-4% incremental increased rate of both cesarean delivery and operative vaginal delivery for fetal distress at 24-33, 34-36, and 37-44 weeks of gestation. Increasing EFM was not associated with any temporal changes in the rate of neonatal seizures. CONCLUSIONS:: The temporal increase in EFM use in the United States appears to be modestly associated with the recent declines in neonatal mortality, especially at preterm gestations. LEVEL OF EVIDENCE:: II