Fetal heart monitoring Health Article

Why the test is performed

Both types of tests are performed to evaluate fetal heart rate and variability between beats, especially in relation to uterine contractions. The tests also indicate the frequency and strength of uterine contractions.

This information is invaluable in determining how well your baby is tolerating the birth process, and if there needs to be emergency intervention.

Normal Values

Normal values indicate that the fetus is not in distress by showing a fetal heart rate between 120 and 160 beats per minute. A variability of 5 - 25 beats per minute from the baseline (normal) fetal heart rate may occur.

The fetal heart rate may drop slightly during a contraction, since placental blood supply is diminished under the compression of a uterine contraction. This is normal as long as the fetal heart rate recovers quickly once the contraction has stopped.

What abnormal results mean

Fetal heart monitoring tests can detect the following abnormal situations or conditions:

• Cord compression (there is no free blood flow to the fetus)
• Fetal heart block (where there is a block of electrical flow within the heart muscle causing an altered heart rhythm)
• Fetal malposition
• Fetal hypoxia (insufficient oxygen supply to the fetus)
• Infection (monitoring cannot diagnose an infection, but can suggest the presence of an infection)
• Uteroplacental insufficiency (insufficient oxygen exchange between the uterus and the placenta)
• Fetal distress
• Abruptio placenta

What the risks are

External fetal monitoring:

• There are no risks associated with external monitoring. Some people believe the test, however, may lead to early delivery, unnecessary cesarean section, and other more invasive forms of delivery. Talk to your health care provider about the use of external monitoring.

Internal fetal monitoring:

• Infection
• Fetal scalp bruising