What's considered a normal fetal heart rate – and how this changes by week

The fetal heart rate is the number of times your baby's heart beats per minute – how fast it's beating. Your doctor or midwife will listen to your baby's heart rate to check on how they're doing throughout pregnancy and during labor, too.

Your baby's heart beats much faster than that of an older child or adult. "They're growing and burning so much energy that an abundance of waste is produced that needs to be removed from the body," says Shannon Smith, M.D., an ob-gyn at Brigham Faulkner Ob/Gyn AssociatesOpens a new window and member of the BabyCenter Medical Advisory Board. "They have very high metabolisms!"

What's a normal fetal heart rate?

Most experts consider between 110 and 160 bpm (beats per minute) to be a normal fetal heart rate through most of pregnancy. (Some use 110 to 150 bpm or 120 to 160 bpm.) Very early on – between 8 weeks and 10 weeks pregnant – the range is higher, between 150 and 170 bpm.

But the rate doesn't stay the same. It changes throughout pregnancy and even throughout the day sometimes. A shift of 5 to 25 beats per minute is perfectly normal.

Sometimes a change in fetal heart rate can signal a problem, however – if your baby isn't getting enough oxygen, for example, or if they have a heart defect.

Your doctor or midwife will start routinely checking your baby's heart rate at your first prenatal visit.

"A fetal heart check is quick and routine," says Dr. Smith. "Most importantly, it's used to ensure that there is a fetal heartbeat. Secondly, we look to see that it's within the normal range. If it isn't, your provider will do further testing to diagnose the problem."

How fetal heart rate changes by week

Here's how your baby's heart rate is likely to change during pregnancy:

• At 5 weeks, your baby's heart rate is about the same as yours, around 80 to 85 bpm.
• By 6 weeks, it has increased to about 110 bpm.
• By 9 to 10 weeks, it has increased to about 170 bpm.
• At 10 weeks, the rate begins to decline and soon falls within the baseline range of 110 to 160 bpm.
• By 14 weeks the fetal heart rate is about 150 bpm.
• By 20 weeks the fetal heart rate is about 140 bpm.
• When your baby is ready for birth, their heart rate is about 130 bpm.

Don't worry if your baby's heart rate doesn't follow this general outline, though.

"While I definitely see this heart rate shift on average across pregnancies, if a single baby doesn't follow this pattern, it's not clinically significant or worrying," says Dr. Smith.

Once your baby is born, their heart rate increases to its normal rate of 110 to 160 bpm within minutes, though this may take longer for preemies. And a newborn's heart rate may be slower while they're sleeping.

Do boys and girls have different heart rates?

You may have heard that a fetus' heart rate can tell you whether you're having a boy or girl, because girls have a faster heart rate than boys. But science doesn't back this up, at least in early pregnancy.

A large reviewOpens a new window of studies concluded that sex-related differences in fetal heart rates in the first trimester are minimal. And, if anything, boys have a slightly higher heart rate than girls.

But fetal heart rates later in pregnancy may tell us more. According to one studyOpens a new window of more than 1,600 fetuses, at the end of pregnancy boys had a lower heart rate than girls when active.

Even if this is true, it's not especially useful, because there's no set heart rate that indicates which sex your baby is. And, there are other, reliable ways to know the sex of your baby.

How your baby's heart rate is monitored

There are several ways to monitor your baby's heart rate:

A handheld Doppler device is what your doctor or midwife will use to check your baby's heart rate at your prenatal visits. They may also use a Doppler to check intermittently during labor. To use a Doppler – which receives and amplifies sound waves – your doctor or midwife will move the gel-covered device around on your belly until they can detect the heartbeat. (Learn more about when you can hear your baby's heartbeat with a Doppler device.)

An electronic fetal monitor can be used to check your baby's heart rate continuously or intermittently while you're in labor. This is done by strapping on a device called a transducer. The transducer transmits your baby's heartbeat to a machine near your bed. Sometimes wireless monitoring is available, which give you more mobility.

Most women will have a heart-rate check when admitted to the hospital. After that, the frequency depends on how your labor is progressing, with more frequent checks usually done during the second (pushing) stage. (The monitor will be taken off and on.) If you have a high-risk pregnancy or are being induced or having your labor augmented, you'll probably be monitored throughout labor.

Internal fetal monitoring. This is done by attaching a wire electrode to your baby's scalp by inserting it through your cervix during labor. Your doctor or midwife may decide to do internal monitoring if the external monitor isn't picking up your baby's heartbeat well enough or if your provider wants a more accurate reading during labor. 

Learn more about how your baby's heart rate is monitored during labor.

What if there's a concern with my baby's heart rate?

If your doctor or midwife notices irregularities with your baby's heart rate, they may do more testing to see what the problem is. A heart rate that's significantly off the expected mark in early pregnancy may mean that a miscarriage is more likely. Later in pregnancy, it may mean that your baby isn't getting enough oxygen or that they have a heart condition.

But an abnormal fetal heart rate isn't necessarily cause for alarm. "Abnormal fetal heart rate patterns do not always mean there is a problem," says the American College of Obstetrics and GynecologyOpens a new window (ACOG).

In fact, Dr. Smith says that in her office, odd fetal heart rates are often due to the mom-to-be needing to eat or drink something.

"I always encourage my patients to hydrate with at least one to two big glasses of water and a snack on the way to their office visit," says Dr. Smith.

During labor and delivery, your doctor or midwife will try to quickly address an irregular heartbeat. Something as simple as changing your position might correct the rate, for example. Or your doctor or midwife may give you more IV fluids, supplemental oxygen, or medication to relax your uterus and slow your contractions. If you're being induced and your baby's heart rate becomes concerning, your provider may stop using Pitocin.

If your baby's heart rate becomes concerning enough and you're far enough along (your cervix is fully dilated), your provider may use assisted delivery techniques (forceps or vacuum extraction). Or they may decide that your baby needs to be delivered as soon as possible via C-section.

When to call your doctor or midwife

You won't be able to tell if your baby has a change in heart rate, but there are other signs that you or your baby may need help.

Call your doctor or midwife or go to the hospital right away if you think your baby's movements have decreased or become weaker, or if they suddenly feel excessively active. A change in movement may mean that your baby is in distress. It's a good idea to be aware of your baby's fetal movement patterns so you'll recognize sudden changes.

Also call if you have:

• Bleeding or spotting
• Painful or burning urination
• Unusual vaginal discharge
• Cramping or pain in your abdomen or pelvis
• Pain in your shoulder
• Leaking amniotic fluid
• Intense itching
• Persistent or severe headache
• Rapid weight gain
• Vision changes
• Fever
• Flu-like symptoms
• Severe nausea and vomiting
• Sudden or severe swelling
• Dizziness or fainting
• Sudden, severe, or constant shortness of breath
• Extreme fatigue
• Feelings of depression or anxiety