Electronic Fetal Heart Monitoring

Submitted by Nic on November 20, 2012

Pregnancies can sometimes have mild to severe complications. However, machines such as an electronic fetal monitor (EFM) can help prevent some of the complications associated with pregnancy, such as cerebral palsy (brain damage that causes physical impairment) and seizures in new born babies. But do these really work? Recent research indicates that high reliance on these machines has resulted in unnecessary increase in cesarean rates.

Let's find out what this piece of equipment is all about.

During pregnancy, especially the third trimester and during labor, electronic fetal heart rate monitoring is often done to prevent complications. Below are some of the complications that EFMs help prevent.

  • Seizures in the infant
  • Cerebral palsy
  • Perinatal death

Electronic Fetal Heart Monitoring During Pregnancy

The heart rate of the fetus can be monitored both externally over the abdomen and internally through the vaginal cavity. Separate devices are used for external and internal monitoring. The heart rate of the fetus is monitored internally only when complications are suspected.

Normal heart rates of the fetus during pregnancy are

  • Week 5 – 80 to 103 bpm (beats per minute)
  • Week 6 – 103 to 126 bpm
  • Week 7 – 126 to 149 bpm
  • Week 8 – 149 to 172 bpm
  • Week 9 – 155 to 195 bpm

Drastic variations usually suggest complications, and your obstetrician would certainly be able to detect them during routine checkups.

Tests Conducted

Fetal heart rates are monitored using two tests.

  • Non-stress test: In the non-stress test, the heart rate of the fetus is monitored when the fetus moves. This test helps to detect the amount of amniotic fluid present.
  • Contraction stress test: In the contraction stress test, the baby's heart rate is monitored during contractions. This test helps determine whether or not the baby will be able to cope with its own movements and the contractions during labor.

Normal Electronic Fetal Heart Monitoring

Normal fetal heart rate is usually monitored externally by using a special stethoscope or an electronic fetal heart rate monitoring device. The device is usually placed on top of the stomach and held in place using straps. The heart rate of the fetus is monitored through sensors that reflect sound waves (ultrasound), providing you with an accurate heart beat per minute (bpm).

Contractions

Along with heart rate, most fetal heart rate monitors also monitor the rate of contractions. This will help determine if the contractions are normal. Fetal heart rate monitors will monitor the following with regards to contractions during labor.

  • Frequency of contractions
  • Duration of contractions
  • Intensity of contractions
  • Resting tone (how relaxed the fetus is between contractions)
  • Interval between contractions

Today, electronic fetal heart monitoring is so common that most hospitals in the US and around the world use it as a standard practice during childbirth. Although cesareans have increased with the use of EFM, their help in preventing complication during childbirth merits the use of these devices during childbirth.

References

  • www.webmd.com/baby/electronic-fetal-heart-monitoring
  • Renu Misra and Hans S. Grundsell (2004), Electronic Fetal Heart Monitoring, BI Publications Pvt. Ltd., Delhi.
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