McKesson Clinical Reference Systems: Women's Health Advisor 2002.2

What is internal fetal monitoring?

Fetal monitoring measures the baby's heart rate and the mother's contractions during labor. A fetal monitor may be external or internal. For external monitoring, instruments are held in place on the mother's abdomen by two belts. Internal fetal monitoring uses an instrument that goes into the mother's uterus and an instrument that is connected directly to the baby. The instruments produce graphs that can be viewed on a screen. This information helps your health care provider know how the baby is doing during labor.

Although internal and external monitors record the same information, internal monitoring is more accurate.

When is it used?

Your health care provider will use internal monitoring if:

• The results of external monitoring are abnormal.
• Your provider wants to watch the baby's condition more closely.

Your health care provider may also use internal fetal monitoring if:

• The external monitor is not recording accurately.
• You have a high-risk pregnancy.
• The baby has an abnormal fetal heart rate or it is likely the baby will experience distress.
• Your provider wants to measure the strength of your contractions.
• You are given the drug oxytocin, which helps stimulate contractions.

When is it not used?

The membrane and fluid surrounding the baby (often called the bag of water) must be broken to insert an internal monitor. For this reason there are times when your health care provider will not use the test. You will not have internal monitoring if:

• Your placenta is covering the opening to the uterus (a condition called placenta previa).
• The baby is too high in the uterus and breaking the bag of waters could be dangerous.
• You have a herpes or strep infection. Using an internal monitor could increase the chance of spreading the infection to the baby.
• The baby or the labor is premature. Your doctor would not break the bag of water in this case because it would make you go into labor.

What happens during the procedure?

A fetal scalp electrode and an intrauterine pressure catheter are used. The electrode is a small wire. It is placed directly on the baby's scalp and records the baby's heart rate. The catheter is a narrow tube inserted into the uterus. A pressure gauge attached to the catheter measures the strength of your contractions.

What are the risks associated with this procedure?

Complications from this test are rare. They may include the following:

• The spiral electrode may cause an infection on the baby's scalp.
• Improper placement of the electrode may hurt the baby.
• The catheter placed in the uterus may cause bleeding in the mother if it goes through the placenta or the uterine wall. Also, it may cause the uterus to become infected.

This content is reviewed periodically and is subject to change as new health information becomes available. The information is intended to inform and educate and is not a replacement for medical evaluation, advice, diagnosis or treatment by a healthcare professional.