To check how your baby is doing prior to labor and delivery, his or her heart rate is monitored with special equipment. This is called fetal heart rate monitoring. Most babies will have changes in their heart rates in the last trimester of pregnancy. These are normal. However, some changes in the heart rate of the baby can signal a problem. Fetal monitoring cannot prevent a problem from occurring. However, it can alert our doctor or nurse to warning signs and allow them to take steps to help the baby.
Electronic fetal monitoring uses special equipment to measure the response of the baby’s heart rate while the baby is at rest, and the response to contractions of the uterus (if they are present). It provides an ongoing record that can be read by the doctor or nurse. You are reclining in a comfortable lounge chair during electronic monitoring. You can move around and find a comfortable position.
A pair of belts is comfortably wrapped around the mother’s abdomen. One device uses Doppler to detect the fetal heart rate. The other device measures the presence and length of contractions.
What Do Fetal Heart Rate Patterns Mean?
It is normal for a fetal heart rate to vary between 110 and 160 beats a minute. This is much faster than your own heart rate, which is about 60–100 beats per minute. A heart rate in your baby that doesn’t vary or is too low or too high may signal a problem. Changes in the fetal heart rate that occur along with contractions form a pattern. Certain changes in this pattern may suggest a problem.
If there is an abnormal fetal heart rate pattern, to help the baby you may be:
- Asked to change positions
- Given oxygen through a mask
- Given fluids
- Given medication to weaken contractions and relax the uterus
- Sent to labor and Delivery for more extensive monitoring
Abnormal fetal heart rate patterns do not always mean there is a serious problem. Other tests may be needed to get a better idea of what is going on with your baby.
If test results suggest your baby has a problem, your doctor may decide to deliver the baby right away. In this case, the delivery of the baby is more likely to be by cesarean birth.