Fetal ECG Readings Offer No Advantage During Labor

A new technology that provides electrocardiogram (ECG) readings of the fetus heart during the birth process offers no advantages over conventional monitoring, according to a new study.

Researchers at the US National Institute of Child Health and Human Development (NICHD; Bethesda, MD, USA), the University of Texas Medical Branch (UTMB; Galveston, USA), and other institutions conducted a multicenter trial in which 11,108 women attempting vaginal delivery at more than 36 weeks of gestation were randomly assigned to open or masked monitoring with fetal ECG ST-segment analysis; the masked system functioned as a normal fetal heart-rate monitor, while the open system displayed additional information when uncertain fetal heart-rate patterns were detected.

In all, 5,532 women were assigned to the open group and 5,576 to the masked group. The primary outcome—a composite of intrapartum fetal death, neonatal death, an Apgar score of 3 or less at five minutes, neonatal seizure, an umbilical-artery blood pH of 7.05 or less with a base deficit of 12 mmol per liter or more, intubation for ventilation at delivery, or neonatal encephalopathy—occurred in 52 fetuses of women in the open group (0.9%) and 40 fetuses or neonates of women in the masked group (0.7%).

Among the individual components of the primary outcome, only the frequency of a 5-minute Apgar score of 3 or less differed significantly between neonates of women in the open group and those in the masked group (0.3% versus 0.1%). There were no significant between-group differences in the rate of cesarean delivery or in fact any operative delivery. Adverse events were rare, and occurred with similar frequency in the two groups. The study was published on August 13, 2015, in the New England Journal of Medicine (NEJM).

“The study authors compared a number of outcomes —fetal and newborn death, seizures, and cesarean delivery—and found no significant differences,” said study coauthor Uma Reddy, MD, of the NICHD research network. “Even though a new treatment or technology may appear promising, it really isn’t possible to know whether it provides any benefits unless it’s tested in a research study. Our study didn’t find any benefit for ECG ST monitoring in term births.”

ECG fetal ST segment analysis explores the ST interval, the time after a heartbeat during which the heart cannot contract, which lasts until the heart cells recover from the electrical impulse that triggered the beat. The idea behind fetal ECG ST monitoring was that additional information about the heart would alert delivery room staff earlier than would heart rate monitoring alone, allowing them to intervene earlier to prevent potential complications.

Related Links:
US National Institute of Child Health and Human Development
University of Texas Medical Branch