Baby heart rate monitors were first used in the fifties to check for pregnancy abnormalities. Today, they are used as part of routine pre-natal visits to ensure the health of the baby. A baby monitor system is also used during labor to monitor the strength and duration of the contractions. The fetal heart monitor uses Doppler ultrasound technology to detect blood flow, oxygen levels and heartbeats.

A baby heart rate monitor is available in external and internal types. Using an external baby monitor system during pregnancy will report the baby's heart rate, measure the duration of contractions, tests for infant stress and evaluate amniotic fluid levels. This type of baby infant monitor may be a stethoscope, two flat elastic sensors or an ultrasound machine. Sometimes the information is heard as a beeping sound, while other times, a chart reading is printed out. Heart monitor readings are a great way to ensure the health of the baby and sense uterine contractions during labor.

For the most part, baby heart rate monitors are just a normal part of pregnancy care. However, there are also some special reasons why someone may opt for more frequent monitoring. For instance, mothers with diabetes may want their babies tested for high blood pressure. Mothers who are over 41 weeks pregnant may want to check their baby's health to see what the hold up is. If delayed fetal growth is revealed through the ultrasound, then the doctor may want to use the baby breathing monitor, as well as the ultrasound video monitors, to see if there may be trouble with uterine oxygen levels.

To prepare for heart rate monitors testing, mothers may be asked to eat a meal shortly before the non-stress test because food digestion will increase the baby's movements. Conversely, contraction tests may require mothers to abstain from eating or drinking 4 to 8 hours prior to monitoring. Mothers who smoke will need to avoid smoking for two hours before the test because smoking decreases the baby's activity. Doctors will check to see that the baby's heart rate is between 120 to 160 beats per minute. If abnormal readings occur, sometimes ultrasound video monitors will be consulted and blood samples will be taken.