Electronic Fetal Heart Monitoring
How It Is Done continued...
nonstress test, the sensors are placed on your belly. You may be asked to push
a button on the machine every time your baby moves or you have a contraction.
Your baby's heart rate is recorded and compared to the record of movement or
your contractions. This test usually lasts about 30 minutes.
For internal monitoring, you
will usually lie on a bed on your back or left side. A thin wire (electrode)
will be guided through your vagina and cervix and attached to your baby's
scalp. A small tube is also inserted through your vagina to connect a device
that monitors the contractions inside your uterus. A belt is placed around your
upper leg to keep the monitor in place. The electrode and the tube are attached
with wires to a recording device that can show or print out a record of
your baby's heart rate as well as the strength and duration of your uterine
How It Feels
Lying on your back (or side) while you
are being monitored may be uncomfortable or painful if you are having labor
contractions. The belts holding the monitors in place may feel tight.
You may be able to change positions or move around more during internal
electronic fetal heart monitoring than during external monitoring.
Placing the internal monitor into your uterus may be mildly
Studies show that electronic fetal monitoring
may be linked to an increase in cesarean deliveries and in the use of a vacuum
or forceps during delivery.1
There is a
slight risk of infection for your baby when internal monitoring is done.
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. The results of electronic fetal heart
monitoring are usually available immediately.
Electronic fetal monitoring
Your baby's heart rate is 110 to 160 beats per
Your baby's heart rate increases (accelerates) when he
or she moves and when your uterus contracts.
Your baby's heart rate drops during a contraction but
rapidly returns to normal after the contraction is over.
Uterine contractions during labor are strong and
Your baby's heart rate is less than 110 beats per
Your baby's heart rate is more than 160 beats per
nonstress test, your baby's heart rate does not
increase by 15 beats per minute or drops far below its baseline rate
(deceleration) after he or she moves.
Uterine contractions are weak or irregular during
What Affects the Test
Reasons you may not be able to
have the test or why the results may not be helpful include:
- Smoking cigarettes or using other tobacco
products and drinking or eating large amounts of caffeine (such as from several
cups of strong coffee), which can falsely raise your baby's heart
- Extra noises such as your heartbeat or your stomach
- Your baby is sleeping during a nonstress
- Problems with the placement of the external monitoring
device. These problems may include:
- Your baby is moving a lot during the
- You are pregnant with more than one baby, such as twins or
- You are overweight.