External fetal monitoring is a test used during pregnancy. It measures a baby's heart rate and the mother's contractions. The test uses instruments placed on the mother's belly to make the measurements. The results are viewed as graphs on a video screen.
The information about the baby's heart rate and how it changes with contractions helps your healthcare provider know how the baby is doing. It also shows how strong and frequent your contractions are.
External fetal monitoring is done to see how a baby is doing during labor and delivery. It may also be done before labor to check on the baby’s health.
Fetal monitoring is usually done the entire time you are in labor. It’s especially needed if your pregnancy is high risk. For example, continuous monitoring during labor is needed in cases of:
If your pregnancy is low risk, a monitor may be used for only about 20 minutes at the start of labor and then off and on for a few minutes each hour.
The instruments used for external monitoring are held in place with 2 elastic belts around the mother's abdomen. A pressure gauge is on one of the belts. The gauge records the contractions. Attached to the other belt is a small ultrasound instrument. It records the baby's heart rate.
Monitoring is safe and fairly comfortable. You can change positions while the devices are in place, but movement sometimes disrupts the test recording.
When the baby's heart rate is normal, the monitor may be disconnected at times. You can then move more freely. When the monitor is not being used, your healthcare provider may check the baby's heart rate with a stethoscope.
If the external monitor shows that the baby's heart rate is abnormal or your contractions are too frequent there may be a concern that the baby is not getting enough oxygen. An internal monitor may then be used. An internal monitor uses instruments inside the uterus and on the baby’s scalp. It can give more accurate information.
If the baby’s heart rate is too slow or does not change as it should with contractions, it may mean that the baby is not getting enough oxygen. Your provider may decide that the baby needs to be delivered by a cesarean section (C-section).
Fetal monitoring allows your healthcare provider to check the baby's response to contractions and labor. If there is concern about how the baby is doing, more tests may be done. If the monitor shows a normal pattern, it can be reassuring to you and your healthcare provider.
External fetal monitoring has no known serious risks when the information it provides is used properly. Sometimes the information from the monitor may not be completely accurate. The monitoring should be done by someone who is trained in interpreting it and who is able to carefully weigh other signs of the baby's health.