Aiming to Avoid the Scalpel
The Unkindest Cut
March 19, 2001 -- Kathy Schuler dreaded the thought of a
cesarean section. She had seen friends struggle through recovery and hated the
idea of being cut open. But after five hours of labor and signs that her baby
might be in trouble, there usually was no other choice in cases such as hers.
A new device called the fetal oxygen saturation monitor,
designed to measure the level of oxygen in a fetus' blood, is giving doctors,
nurses, and expectant mothers the reassurance that babies who may seem to be
struggling during labor are actually fine.
"From my perspective, this is one of the most significant
technological advancements in obstetrics in a long time," says Thomas J.
Garite, MD, professor and chairman of obstetrics and gynecology at the
University of California-Irvine. "It is technology that allows us to do the
right thing for the right reason, and that is an important advance."
For the past 30 years, doctors and nurses have monitored fetal
condition through the heart rate monitor -- a belted device that is strapped
around the mother's belly. However, about 30% of all labors (about 1.2 million
births per year) will produce an abnormal or "nonreassuring" heart rate
at some point, according to the CDC. Such an abnormal rate could be due to a
serious concern such as the baby receiving an insufficient amount of oxygen.
But it also could be due to an inconsequential one like the baby falling
asleep. Unfortunately, the heart monitor is usually not capable of
distinguishing between the two, leaving the obstetrical team with the difficult
decision of whether to allow labor to continue or proceed with a C-section.
About seven of every 10 cesarean sections performed because of
presumed fetal distress are unnecessary, says Kathleen Simpson, PhD, RN, a
nurse researcher in labor and delivery at St. John's Mercy Medical Center in
St. Louis. However, the fetal oxygen saturation monitor, approved by the FDA
last year, has the potential to change that. Called by the FDA "the first
major technological development in fetal monitoring" in decades, the
OxiFirst system takes some of the guesswork out of deliveries.
"It gives more information and objective information so we
can say, 'This baby needs to come out and needs to come out in an emergency
fashion,' or 'This baby can tolerate labor a little longer and perhaps have a
vaginal birth,'" says Simpson, a co-investigator in the multicenter study
on fetal oxygen monitors.
In the past, medical teams have used fetal scalp blood sampling
to determine fetal oxygen levels, but Simpson tells WebMD the process of
obtaining the blood from the baby's scalp is invasive, and often must be
repeated several times.
The fetal oxygen monitor, on the other hand, usually causes no
more discomfort than a traditional vaginal exam, Simpson says. A disposable
sensor connected to a cable is inserted through the birth canal after rupture
of the amniotic membranes ("breaking of water"), and rests against the
baby's cheek, temple, or forehead, pressing up against the uterine wall. Using
red and infrared light, the sensor analyzes the fetus' blood oxygen level, and
this information is displayed on a monitor, providing real-time data to the OB