What is FHR in Pregnancy?

The health and well-being of a developing baby is measured in terms of several parameters. One such parameter that you will often find your doctor talking about is FHR. For those of you who do not know what is FHR in pregnancy, we have put together this detailed write-up wherein you will find what FHR is, how it is measured, what’s normal, what’s not, and other relevant information you must be aware of.

The full form of FHR is Foetal Heart Rate. It is a parameter that tells about how many times a baby’s heart is beating in one minute and how well the baby is doing. This test is done during pregnancy when the baby is still in the mother’s womb.

FHR is usually higher than that observed in adults and children. So, don’t be surprised if you hear your doctor giving a higher number. As babies in utero are growing and developing, their metabolism is higher, and so is the foetal heart rate.

On regular prenatal visits, doctors usually use a Doppler to monitor foetal heart rate. This handheld device is covered with a gel and moved over the mother’s abdomen to pick up and amplify the baby’s heartbeat. A doppler can also be used during labour to check the heart rate of the baby.

Other ways to monitor FHR include using an electronic foetal monitor or an internal foetal monitor. When the electronic foetal monitor is used, a transducer is wrapped around the mother’s belly to check the foetal heart rate. 

On the other hand, when the doctor chooses internal foetal monitoring, a wire electrode is placed over the baby’s scalp from the outside through the cervix to monitor the foetal heartbeat. Internal foetal monitoring is done during labour, if needed.

Foetal heart rate does not remain the same throughout pregnancy and keeps changing all along. A general guideline to foetal heart rate is as follows:

At week 5-7: 90-110 BPM

At week 8-12: 140-170 BPM

At week 13-26: 110-160 BPM

At week 27-40: 110-160 BPM (drops slightly closer to delivery)

You will likely hear your baby’s heartbeat during your 10–12-week prenatal appointment. As you can see in the above section, the foetal heart rate remains between 110-160 BPM for most part of the gestation period. This average is usually considered as normal for a developing baby.

Foetal heart rate or FHR is considered abnormal when the number of beats per minute are either less than 110 or more than 160. A foetal heart rate with less than 110 beats per minute is termed bradycardia, whereas when FHR is more than 160 beats per minute, it is called tachycardia. Both these conditions are not very common and may resolve in some time.

When abnormal foetal heart rate persists for a long time, it may indicate problems like foetal distress, infection, or poor transmission of electrical signals within the heart. In situations like these, doctors closely monitor the baby while the mother is in the hospital and may use medications or other interventions for the baby’s safety.

An abnormal FHR can be due to many factors. Here are some reasons for abnormal foetal heart rate:

Factors related to maternal health

• Hyperthyroidism
• Fever
• Infections
• Diabetes

Factors related to foetal health

• Anaemia
• Infection
• Injury to central nervous system
• Congenital heart disease

Other factors

• Certain medications
• Poor blood flow to the heart
• Imbalance in electrolytes
• Foetal distress

If your doctor notices an abnormality in the foetal heart rate, they may order additional tests to figure out the exact cause behind the irregularity. In some cases, an abnormal FHR may indicate chances of miscarriage or poor oxygen supply to the baby. In other instances, it may highlight a heart condition.

But many times, the reason for temporary irregularities in foetal heart rate can be due to simple reasons such as the need to eat or drink something before the test.

Many times, an abnormal FHR is not a cause for concern. But when it is, doctors usually try the following methods to bring the foetal heart rate back to normal:

• Supplementing the mother with extra oxygen
• Administering IV fluids
• Changing positions
• Using medicines to slow down contractions during labour

When these methods don’t help, the doctor may suggest immediate delivery via c-section or using other tools for delivery.

Studies have revealed the link between foetal heart rate and miscarriage. It is determined that the chance of miscarriage is high when the foetal heart rate is lower than what it should be. The results showed a 21% chance of miscarriage when the foetus had a low FHR and a smaller crown-to-rump length (CRL in pregnancy).

While you won’t be able to identify if your baby’s heart rate has changed, there are some subtle signs that you can notice and see your doctor if need be. Always be mindful of your baby’s movements.

Identify what’s normal for you and your baby. In case you notice changes in your baby’s activity level, for example, slower or decreased movements than usual or moving excessively suddenly, see your doctor right away.

FHR in pregnancy means the foetal heart rate. It is a very important parameter that tells a lot about the health and well-being of a growing baby. FHR is monitored intermittently throughout pregnancy to see how the baby is doing. Normal foetal heart rate is typically between 110-160 beats per minute. Anything less or more is considered abnormal and calls for your doctor’s attention.

By closely monitoring FHR, doctors and parents can gain reassurance and make decisions about the baby’s health.

What is a normal FHR level?

A normal foetal heart rate ranges between 110 to 160 beats per minute, though it may vary a bit depending on the stage of pregnancy.

How is foetal heart rate measured?

Foetal heart rate is measured using a Doppler device or an electronic foetal monitoring device during prenatal visits.

Does foetal heart rate change throughout pregnancy?

Yes, foetal heart rate changes throughout pregnancy. It starts with a higher number during early pregnancy and gradually slows down to a stable rate in later months of pregnancy.

Can FHR determine a baby’s gender?

No, FHR cannot determine a baby’s gender as there is no evidence supporting this claim. The idea that higher foetal heart rates indicate a girl and lower foetal heart rates indicate boys is a myth.

How can I monitor my baby’s heart rate at home?

Some parents use a Doppler device at home to monitor their baby’s well-being. However, doctors recommend relying on regular checkups for better monitoring of the baby’s health.

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