What Is a Normal Fetal Heart Rate?

Is my baby's heart beat too fast?

Couple listening to baby's heartbeat during ultrasound
Blend Images - Jose Luis Pelaez Inc/Getty Images

How do you know if your baby's heart rate is normal? This is a question that you probably have from the first time you hear your baby's heartbeat. What you hear might really surprise you. Most people are not prepared for how quickly a baby's heart beats in pregnancy.

Though there are many words to describe the moment that you first hear your baby's heartbeat, most people use words like galloping to describe how the heart rate sounds.

While the heart rate in pregnancy is faster than an adult's heart rate, the truth is that a normal fetal heart rate changes during the stages of pregnancy.

How Your Baby's Heart Rate Changes

At about five weeks gestation, your baby's heart begins to beat. At this point, a normal fetal heart rate is about the same heart rate as the mother's: 80 to 85 beats per minute (bpm). From this point, it will increase its rate about three beats per minute per day during that first month.

This is so exact that your doctor or midwife can actually use heart rate to help pinpoint the gestational age of your baby via ultrasound. The miscarriage rate for pregnancies in which a mother has heard or seen a heartbeat is lower; however, if your doctor notices that your baby's heartbeat is off by a week or more, it can indicate that a miscarriage is more likely.

By the beginning of the ninth week of pregnancy, the normal fetal heart rate is an average of 175 bpm.

At this point, it begins a rapid deceleration to the normal fetal heart rate for mid-pregnancy to about 120 to 180 bpm. There is also a slowing of the normal fetal heart rate in the last 10 weeks of pregnancy, though the normal fetal heart rate is still about twice the normal adult's resting heart rate.

Natural Heart Rate Fluctuations

Your baby's normal fetal heart rate will also vary naturally, just as your heart rate does. Movement, sleeping, and other activities can cause normal variation. Be sure to talk to your midwife or doctor about concerns that you have with your baby's heart rate.

If you are having a non-stress test at the end of pregnancy, you can hear the fluctuations of the heart rate. The heart rate goes up and down within a certain framework of normal. Imagine what it would sound like if you had an ongoing audio of your heart rate as you were starting to exercise and then cooling down. Your heart rate would go up and down as well. Your baby has the same reaction to exercising via movement.

Monitoring Your Baby's Heart Rate at Home

Some moms feel better when they can monitor the baby's heartbeat from home. This use of a doppler in the home is not recommended for most mothers. The concerns are multi-pronged and include overuse of the doppler listening device and/or misinterpretation, positively or negatively.

There are other ways to listen to your baby's heartbeat. You should talk to your doctor or midwife about how to best monitor your baby if you are concerned.

Fetal Monitoring in Labor

Fetal monitoring in labor can be done by the use of intermittent auscultation, which means listening with a stethoscope, fetoscope, or handheld doppler at various points in labor.

You can use intermittent electronic fetal monitoring via external monitoring belts. Or you can have continuous fetal monitoring with either external monitoring or internal fetal monitoring.

Each of these has benefits and tradeoffs for you and your baby, depending on your labor and your medical history. Talk to your doctor or midwife for advice on which is best for you. In general, low-risk women will need less monitoring in labor. However, during the process of labor, your baby may show signs of needing more intense monitoring or your labor or interventions may require increased monitoring to help boost the safety of procedures.

For example, even if you are low risk, if you have a Pitocin induction of labor you will likely have continuous external monitoring.

A Word From Verywell

You may worry when you first hear the heartbeat that something is wrong because it sounds so different than what you may be used to hearing. Rest assured, it is most likely normal. Simply ask your practitioner for advice if you are concerned.

Sources:

American Congress of Obstetricians and Gynecologists. (2009). “ACOG Practice Bulletin No. 106: Intrapartum fetal heart rate monitoring: nomenclature, interpretation, and general management principles.” Obstetrics and gynecology 114(1): 192-202.

As Low As Reasonably Achievable (ALARA) Principle. American Institute for Ultrasound in Medicine. 

Obstetrics: Normal and Problem Pregnancies. Gabbe, S, Niebyl, J, Simpson, JL. Seventh Edition; 2016.

Stamatopoulos N, Lu C, Casikar I, Reid S, Mongelli M, Hardy N, Condous G. Prediction of subsequent miscarriage risk in women who present with a viable pregnancy at the first early pregnancy scan. Aust N Z J Obstet Gynaecol. 2015 Oct;55(5):464-72. doi: 10.1111/ajo.12395. Epub 2015 Aug 21.

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