Electronic Fetal Monitor

The electronic fetal monitor (EFM) is an ultrasonic device that records the baby's heartbeat and the relative strength of a contraction.  Results are then recorded on a running strip of paper. The advantages of electronic monitoring are that it is widely available and that it can be used when continuous monitoring is specifically medically indicated.  However, that is where the advantages end and the drawbacks begin.

EFM comes with many disadvantages, including a very high rate of false indications of fetal distress.  It has been shown to increase rates of cesarean section without true medical indication without improving outcomes for the mother or baby.

It is also very uncomfortable and severely restricts movement, thus making labor more uncomfortable and increasing request for mediations during labour, each of which carry their own risks of complications.  It also makes some labor and birth positions impossible, thus increasing the risks of a malpositioned baby or failure to progress or uneven dilation. It can also lead to the need for catheterization should the mother not be able to freely move to the bathroom nor use a bed pan.

In addition, such monitoring reduces the occurrence of 1:1 care.  A single nurse is assigned to many mothers and watches the heart tone readings from a monitor in the nurse's station rather than maintaining face-to-face contact with each mother.  This opens the door for true complications to arise in the even that the monitor malfunctions. In addition, the most common childbirth complications, maternal hemorrhage and a baby that does not breathe on its own soon after birth, cannot be detected with this method.

As with all ultrasound technologies used during pregnancy and birth, there is no long-term evidence to determine safety of an electronic fetal monitor, including duration and exposure levels to the high-frequency sound waves used.  The animal research performed to date shows that such waves caused tissue damage in animals.  More research is needed to provide adequate information on the risks and benefits of routine use during labor.

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Page Last Modified by Catherine Beier, MS, CBE