Electronic Fetal Heart monitoring (EFM) is the most common obstetric procedure performed in the United States. Intended to determine the baby’s well-being during labor, it’s now a routine element in at least 85 percent of labors, up from 45 percent in the 1980s. But it has proved to be a very imprecise tool.
Introduced in the 1970s, EFM was supposed to decrease perinatal mortality and cerebral palsy (CP) by detecting fetal heart rate patterns that indicate oxygen deprivation during labor. Doctors could then deliver quickly, usually by Cesarean section. Problem is, EFM’s false-positive rate for predicting CP is greater than 99 percent. “EFM hasn’t reduced perinatal mortality or CP at all,” says George Macones, M.D., vice chairman of the Committee on Obstetric Practice at the American College of Obstetricians and Gynecologists. CP rates have essentially remained the same since World War II despite advancements in treatments and interventions.
“EFM isn’t currently a good indicator for when babies are in trouble,” Macones explains. “What we’ve done is increase the number of C-sections in response to highly subjective EFM interpretations.” In one experiment, four obstetricians examined 50 EFM tracings (printouts of the fetal heart rate). Their interpretations were the same in only 22 percent of cases. Two months later, the OB re-evaluated the tracings and changed their minds in 1 out of 5 cases.
Making a Dull Tool Sharper
Imperfect as it is, EFM is the standard of care in modern obstetrics. “EFM is currently the best map for a healthy birth, though sometimes it steers us in the wrong direction,” says Marc Jackson, M.D., a maternal-fetal medicine specialist at Salt Lake City-based Intermountain Healthcare (IH), whose 22 percent C-section rate is among the lowest in the U.S. “Our goal is to improve interpretation by creating a better map.”
Macones and Jackson believe new guidelines will reduce subjectivity and more accurately identify the need for intervention. The new classifications:
Category 1 tracings are normal; monitoring may be intermittent. (Women with preeclampsia, type I diabetes or suspected fetal growth restriction require continuous monitoring.)
Category 2 tracings are indeterminate; further continuous monitoring and evaluation are needed.
Category 3 tracings are abnormal, and prompt evaluation and interventions, such as giving the mother oxygen, are required. If there’s no improvement, the baby should be delivered ASAP.
An IH-designed pilot program in which third-party nurse-experts review EFM tracings to provide objective consultations has shown promising results. In the meantime, try to stay healthy during pregnancy and, most importantly, be flexible. “Directions change fast in labor,” Jackson says. “Every doctor wants the best outcome. This is the map we’re following now.”
Find out more about the rise in c-section rates in the United States, click here.