Everything You Need to Know About Your Baby’s Heart Rate During Pregnancy

Author: Dr. Caledonia Buckheit, M.D.

Published: January 25, 2026

One of the most exciting moments during pregnancy is hearing your baby’s heartbeat for the first time. Throughout your pregnancy and during labor, your healthcare team will monitor your baby’s heart rate and you may find yourself wondering what the significance of the actual rate is. This blog will help you understand what’s normal when it comes to your baby’s heart rate, when you can expect heart rate monitoring, and why it’s important.

In this blog post:

• What is a Normal Fetal Heart Rate?
• Does Fetal Heart Rate Predict the Sex of the Baby?
• When is it Important to Listen to the Fetal Heart Rate?
• Why Do We Monitor Fetal Heart Rate in High-Risk Pregnancies?
• Fetal Heart Rate Monitoring During Labor and Delivery
• The Bottom Line

What is a Normal Fetal Heart Rate?

While a typical adult heart rate is 60-100 beats per minute (bpm), your baby’s heart beats much more rapidly. And just like you, your baby’s heart rate varies depending on their environment and activity level. So don’t be worried if at every appointment you are told a different heart rate number—this is normal and expected! If they are in a sleep cycle, for example, their heart rate will be lower than if they are kicking and rolling. 

First Trimester (Weeks 1-13)

During early pregnancy, your baby’s heart rate is at its fastest. It typically peaks around 170–175 bpm at 8–9 weeks, and then gradually decreases from there. The average fetal heart rate during the first trimester is around 152 bpm, but the normal range is between 110-160 bpm.[1] When you have your first ultrasound in those early weeks, seeing and hearing that rapid heartbeat is often one of the most memorable moments of the pregnancy.

Second Trimester (Weeks 14-27)

As your baby grows, the heart rate gradually slows down slightly. During the second trimester, the average fetal heart rate is approximately 146 bpm, still within the normal range of 110-160 bpm. 

Third Trimester (Weeks 28-40)

By the third trimester, your baby’s heart rate continues to decrease slightly as the nervous system matures. The average heart rate is around 143 bpm, with the normal range remaining 110-160 bpm. At term (37-41 weeks), a range of 120-160 bpm has been shown to perhaps be the most accurate “normal range”.[1] 

These slight decreases in heart rate as pregnancy progresses are completely normal and reflect your baby’s developing nervous system and maturation.

Does Fetal Heart Rate Predict the Sex of the Baby?

You may have heard the old wives’ tale that a faster heart rate means you’re having a girl, while a slower heart rate means you’re having a boy. This is a myth. While it’s a fun guessing game, scientific research has consistently shown that fetal heart rate cannot reliably predict your baby’s sex.[2]

Studies have found that while there may be very small statistical differences between male and female fetuses (with females having slightly higher heart rates on average), these differences are minimal—less than 1 beat per minute in most studies.[3] This tiny difference is far too small to be detected by your or your doctor, so not really useful for predicting whether you’re having a boy or a girl.

The most reliable ways to determine your baby’s sex are through ultrasound exam (typically at the anatomy scan around 20 weeks) and genetic testing, not by listening to the heart rate.

When is it Important to Listen to the Fetal Heart Rate?

Your healthcare provider will check your baby’s heart rate at various points throughout your pregnancy and during labor. Here’s when and why:

Early Pregnancy Ultrasounds

During first trimester ultrasounds, your provider will measure the size of the fetus and confirm that there is cardiac activity. Once a fetus measures 6 weeks or more, it is expected to be able to see and measure a heart rate with transvaginal ultrasound. This is an important early indicator of a healthy pregnancy. 

Anatomy Ultrasound (Around 20 Weeks)

At your mid-pregnancy anatomy scan, the ultrasound technician will check your baby’s heart rate along with detailed views of your baby’s cardiac and other anatomy. This comprehensive exam ensures your baby has developed its major organ systems, helps exclude structural abnormalities, and confirms that your baby is growing well.

Routine Prenatal Appointments

At your regular prenatal visits, your provider will use a handheld Doppler to listen to your baby’s heartbeat. This quick check provides reassurance that your baby is doing well. However, keep in mind that feeling regular fetal movement is even more important than hearing the heartbeat when it comes to fetal wellbeing. Recent evidence even suggests that if you can feel your baby moving regularly and you don’t have any high-risk conditions, checking the heart rate at every visit may not be medically necessary! But don’t worry, your providers at Kamm McKenzie don’t have any plans to stop checking the heart rate at your visits; we feel that the benefits of providing reassurance, supplying objective data, and helping our patients bond with their babies justify the practice for all.[4]

During Labor

Monitoring your baby’s heart rate during labor is one of the most important ways your healthcare team assesses how your baby is handling the stress of contractions. This monitoring can be done in two ways:

• Intermittent auscultation: For low-risk labors, your nurse or provider may listen to your baby’s heart rate at regular intervals (every 15-30 minutes during active labor and every 5-15 minutes during pushing) using a handheld Doppler device. This approach allows you more freedom to move around during labor.[5]
• Continuous electronic fetal monitoring: For high-risk pregnancy conditions, or when you’re receiving medications like Pitocin to induce or augment labor, continuous monitoring (with monitors secured with belts around your abdomen) is recommended. Continuous fetal monitoring tracks your baby’s heart rate and your contractions over time, providing important data about how your baby is tolerating the process of labor and delivery.

Why Do We Monitor Fetal Heart Rate in High-Risk Pregnancies?

If you have a high-risk pregnancy—such as diabetes, high blood pressure, decreased fetal movement, or if your baby is measuring small—your provider may recommend additional heart rate monitoring in the third trimester through a test called a non-stress test (NST).[6]

What is a Non-Stress Test?

A non-stress test is a simple, painless test that monitors your baby’s heart rate over 20-40 minutes while you’re resting comfortably. During the test, two monitors are placed on your belly and secured with belts. One monitor assesses the baby’s heart rate, while the other detects contractions. You are typically also given a button to press when you feel your baby move.

What Does the Test Show?

Your healthcare team looks at several features of your baby’s heart rate:

• Baseline: The average heart rate when your baby is at rest
• Variability: Normal, healthy fluctuations in the heart rate from beat to beat
• Accelerations: Brief increases in heart rate, especially when your baby moves
• Decelerations: Any significant decreases in heart rate

What is a “Reactive” NST?

A “reactive” or normal NST shows that your baby’s heart rate increases (accelerates) at least twice during the monitoring period, with each acceleration lasting at least 15 seconds and increasing by at least 15 beats per minute above the baseline. This pattern, along with good variability in the heart rate, is very reassuring and indicates that your baby is getting enough oxygen through the placenta and umbilical cord. 

A reactive NST is highly predictive of fetal well-being over the next several days, which is why this test is often repeated weekly or twice weekly in high-risk pregnancies. This monitoring is especially helpful in conditions that increase the risk of stillbirth, as it provides reassurance that continuing the pregnancy is safe at that time.

Fetal Heart Rate Monitoring During Labor and Delivery

For Low-Risk Labor

If you’re experiencing a low-risk labor without complications and aren’t on Pitocin, intermittent monitoring is an excellent option. Research shows that for healthy women with uncomplicated pregnancies, intermittent monitoring has similar safety outcomes to continuous monitoring but is associated with lower rates of cesarean delivery and operative vaginal delivery.[7]

For High-Risk Labor or Induction

Continuous electronic fetal monitoring is recommended when:

• You’re being induced or your labor is being augmented with Pitocin
• You have a high-risk medical condition (like diabetes or high blood pressure)
• Your baby has shown signs of growth restriction
• You develop complications during labor (such as fever or prolonged labor)
• There are concerns about your baby’s heart rate pattern

Continuous monitoring helps your care team quickly identify any concerning patterns so appropriate actions can be taken to ensure your baby’s safety.

The Bottom Line

Monitoring your baby’s heart rate is an important part of prenatal care and labor management. Understanding what’s normal and when monitoring is necessary can help you feel more informed and confident throughout your pregnancy journey. Remember:

• Normal fetal heart rate ranges from 110-160 bpm throughout pregnancy
• Heart rate cannot predict your baby’s sex
• The type and frequency of monitoring depends on your individual risk factors
• Both intermittent and continuous monitoring during labor are safe and effective when used appropriately

If you ever have concerns about your baby’s heart rate or movement, don’t hesitate to contact us. We are here to provide reassurance and ensure that both you and your baby stay healthy throughout pregnancy and delivery.

References

1. What Is the “Normal” Fetal Heart Rate?. Pildner von Steinburg S, Boulesteix AL, Lederer C, et al. PeerJ. 2013;1:e82. doi:10.7717/peerj.82.
2. The Role of Fetal Heart Rate in First Trimester Sonograms in Prediction of Fetal Sex: A Systematic Review and Meta-Analysis. Nouri S, Kalantar MH, Safi F, Almasi-Hashiani A. BMC Pregnancy and Childbirth. 2023;23(1):582. doi:10.1186/s12884-023-05908-8.
3. Sex Differences in Fetal Heart Rate and Variability Assessed by Antenatal Computerized Cardiotocography. Bhide A, Acharya G. Acta Obstetricia Et Gynecologica Scandinavica. 2018;97(12):1486-1490. doi:10.1111/aogs.13437.
4. Tailored Prenatal Care Delivery for Pregnant Individuals. American College of Obstetricians and Gynecologists, Tiffany A. Moore Simas MD MPH MEd, M. Camille Hoffman MD MSc, et al. American College of Obstetricians and Gynecologists (2025).
5. ACOG Clinical Practice Guideline No. 10:Intrapartum Fetal Heart Rate Monitoring: Interpretation and Management. Obstetrics and Gynecology. 2025;146(4):583-599. doi:10.1097/AOG.0000000000006049.
6. Antepartum Fetal Surveillance: ACOG Practice Bulletin Summary, Number 229. Obstetrics and Gynecology. 2021;137(6):1134-1136. doi:10.1097/AOG.0000000000004411.
7. Approaches to Limit Intervention During Labor and Birth. Allison S. Bryant, Ann E. Borders. American College of Obstetricians and Gynecologists (2019).