What is fetal heart monitoring?

Fetal heart monitoring is done during pregnancy and labor to measure and assess the heart rate the fetus.  The fetal heart rate is an indicator of the fetus’ well-being.  During pregnancy and labor external fetal heart monitoring will be used.  External fetal heart monitoring may be done by listening to the fetal heart beat with a special stethoscope, called a fetoscope, or a hand held ultrasound Doppler placed against the maternal abdomen over the fetus’ back.  Many of the hand-held Doppler’s have speakers so the mother and father can also hear the fetal heart beat.  External fetal heart monitoring can also be done with a flat ultrasound sensor placed on the pregnant abdomen and held in place with an elastic or cloth belt placed around the woman’s back.  This monitor records the fetal heart rate for the entire time the sensor in place.  The fetal heart rate and pattern printed out as a tracing to document the fetal heart activity.  The health care provider can evaluate this tracing to assess the fetus’ status.

During labor, internal fetal heart monitoring may be used.  The cervix must be dilated to initiate internal monitoring.  With internal fetal heart rate monitoring a thin wire with an electrode at the end is passes through the vagina.  The electrode is attached to the fetus’ scalp.  Internal fetal heart rate monitoring provides a more direct measure of fetal heart activity and is used when close monitoring of the fetus during labor is needed.

Fetal heart monitoring measures a baby's (fetus's) heart rate during pregnancy or labor and delivery. These measurements can help health professionals check a fetus's general condition and identify early signs of distress.

During labor and delivery, the fetal heart rate is closely watched along with the mother's uterine contractions (using a tocometer).  This helps the doctor or nurse see how the baby is responding and whether any treatments, such as the use of medicines, are needed to help speed up delivery.

Two types of monitoring—external or internal—can be done:

• For external monitoring, instruments that detect fetal heartbeats are placed around the pregnant woman's abdomen.
• For internal monitoring, electrodes that measure fetal heartbeats are connected to the fetus's scalp. Internal monitoring is not done if there is placenta previa, a condition where the placenta is low and just above the cervix, because of the risk of bleeding.

Whether you have your baby in a birthing center, in the hospital, or at home, your provider will monitor your baby's heartbeat to see how the baby is tolerating labor. Your baby's heart rate will generally range between 110 and 160 beats per minute. During a contraction, the flow of blood to the baby is reduced, and as a result, the baby's heart rate may temporarily go down.

Your provider can listen to the heart rate intermittently or continuously. Most hospitals will require 30 minutes of external fetal monitoring to obtain a baseline reading of your baby's heart rate and response to contractions. From there, your baby's heartbeat can be monitored periodically. Continuous fetal heart rate monitoring is not necessary in most births.

Fetal heart rate monitoring enables health care professionals to monitor your baby's heart rate and check his or her well-being before delivery. This test is generally performed during the last 10 to 12 weeks of your pregnancy. It may be performed earlier if a problem arises during the pregnancy, for example if you develop high blood pressure or if you don't feel the baby moving.