Electronic fetal heart monitoring is done during pregnancy, labor, and
delivery to keep track of the heart rate of your baby (fetus) and the
strength and duration of the contractions of your
uterus. Your baby's heart rate is a good way to tell
whether your baby is doing well or may have some problems.
types of monitoring-external and internal-can be done.
You may have
external monitoring at different times during your pregnancy, or it may be done
External monitoring can be done by listening to your
baby's heartbeat with a special stethoscope. More often, external monitoring is
done using two flat devices (sensors) held in place with elastic belts on your
belly. One sensor uses reflected sound waves (ultrasound) to keep track of
your baby's heart rate. The other sensor measures the duration of your contractions.
The sensors are connected to a machine that records the information. Your
baby's heartbeat may be heard as a beeping sound or printed out on a chart. The
frequency and duration of your uterine contractions are usually printed out on
External monitoring is used for a
nonstress test, which records your baby's heart rate
while your baby is moving and not moving. A nonstress test may be combined with
fetal ultrasound to evaluate the amount of your
External monitoring is also done for a
contraction stress test, which records changes in your
baby's heart rate when you have uterine contractions. It may be done to check
on your baby's health if your baby does not move enough during a nonstress
test. It may help predict whether your baby can handle the stress of labor and
Sometimes external monitoring is done remotely
(called telemetry), without your needing to be connected by wires to a machine.
At some hospitals, the sensors can send the information about your baby's heart
rate and your uterine contractions to a remote monitor, usually at a nurse's
station. Remote monitoring allows you to walk around freely.
Internal monitoring can be
done only after your
cervix has dilated to at least 2 centimeters (cm) and
amniotic sac has ruptured. Once started, internal
monitoring is done continuously.
For internal monitoring, a sensor
is attached to your thigh with a strap. A thin wire (electrode) from the sensor
is inserted through your vagina and cervix into your uterus. The electrode is
then attached to your baby's scalp. Your baby's heartbeat may be heard as a
beeping sound or printed out on a chart. Internal monitoring does not use
reflected sound waves (ultrasound) for monitoring.
A small tube
that measures uterine contractions may be placed in your uterus next to your
baby. The strength and timing of your uterine contractions is usually printed
out on a chart.
Internal monitoring is more accurate than external
monitoring for keeping track of your baby's heart rate and your