Fetal Heart Rate Monitoring: What to Expect

If you’re pregnant your doctor wants to make sure your baby is healthy and growing as he should. One of the ways she does that is to check the rate and rhythm of your baby’s heartbeat.

Fetal heart monitoring is part of every pregnancy checkup. It’s combined with other tests for a closer look if you have diabetes, high blood pressure, or other conditions that could cause problems for you and your baby. Fetal heart rates also can help count your contractions and tell if you’re going into labor too early.

How the Test Is Done

Your doctor can monitor the baby’s heartbeat one of two ways. She can listen for and record the beats from your belly. Or once your water has broken and you’re in labor, she can thread a thin wire through your cervix and attach it to your baby’s head.

From the outside: If your pregnancy is going normally, your doctor likely will check your baby’s heart rate with a hand-held device called a Doppler ultrasound. If you need it, your doctor might do a special test called a nonstress test, usually starting around 32 weeks of your pregnancy. It counts the number of times the baby’s heart speeds up during a 20-minute period.

For the test, you'll lie down with a sensor belt around your belly. A machine will record the number of times the baby’s heart speeds up in a 20-minute stretch. If it’s fewer than 2, your doctor will run a longer test and try to wake the baby or make him stir with noise over your belly.

Your doctor also may put you on a fetal heart rate monitor during your delivery. It can tell your doctor if the contractions are stressing your baby. If so, you might have to have your baby as soon as possible.

From the inside: Once your water breaks and your cervix opens to prepare for birth, your doctor can run a wire called an electrode through it and into your womb. The wire attaches to your baby’s head and connects to a monitor. This gives a better reading than listening to his heartbeat from the outside.

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What the Results Mean

A healthy baby’s heart usually beats 110-160 times a minute in the womb. It speeds up when the baby moves. Signs of possible problems include:

  • Heart beats slower than 110 beats a minute
  • Heart beats faster than 160 beats a minute
  • Heartbeat pattern is abnormal
  • The heartbeat doesn’t go up when the baby moves or during contractions

Lack of a normal heart beat doesn’t always mean something is wrong with your baby. Reasons for it can included medications or his position inside the womb. But lack of a normal heart beat can also be a sign that the baby isn’t getting enough oxygen.

What Your Doctor Can Do

If your baby’s heart rate is not what it should be, your doctor may try several things including:

  • Changing your positions to move the baby
  • Giving you fluids through an IV
  • Having you breathe extra oxygen
  • Relaxing your uterus with medicine to slow contractions
  • Giving you other drugs

If these steps don’t return your baby’s heart rate to normal, you may need to deliver him right away. If your cervix is completely open, your doctor may use a tool called forceps or a special vacuum to pull the baby out instead of waiting for your contractions to push him out. Otherwise, you’ll have the baby by C-section.

WebMD Medical Reference Reviewed by Nivin Todd, MD on December 20, 2017

Sources

SOURCES:

American College of Obstetricians and Gynecologists: “Fetal heart rate monitoring during labor,” “Special tests for monitoring fetal health.”

Johns Hopkins Medicine: “Fetal heart monitoring.”

American Academy of Family Physicians: “Monitoring baby’s heart rate during labor.”

American Family Physician: “Interpretation of the electronic fetal heart rate during labor.”

© 2018 WebMD, LLC. All rights reserved.

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