Pregnancy

Fetal Heart Rate: All the Info

Team Peanut6 months ago6 min read

There are very few things pregnancy that are more awe-inspiring than discovering the fetal heart rate for the first time. Yup, there’s a living being inside you, a little heart very busy at its job of stealing yours.

Ultrasound for fetal heart rate

So when can you expect to hear this magical sound? How is the fetal heartbeat monitored? And what is considered “normal”? We’ve got you.

Table of Contents 📝

  • Fetal heartbeat FAQs
  • Fetal heart rate by week

Fetal heartbeat FAQs

They’re already making your heart skip a few beats—why not investigate what’s going on with theirs? Here’s the lowdown:

When does a fetus have a heartbeat?

As early as 5 to 6 weeks. Wow! (Sidebar: at this early stage, your doc may refer to the little being inside you as an embryo—so, really: you’ll be able to hear the embryo’s heartbeat at about 5 to 6 weeks.)

In most cases, your doc won’t perform an ultrasound till after 6 weeks, so you might have to wait until then to hear that beautiful beat. (Sorry, mama!)

However, in some cases, a transvaginal ultrasound may be performed sooner than this, usually to check for complications, like ectopic pregnancies. If this is the case for you, you may get a sneak peek of the beat a little earlier than expected.

What is a normal fetal heart rate?

So what is a good fetal heart rate? While it varies at different stages of your pregnancy, the average fetal heart rate is between 110 and 160 beats per minute.

If the fetal heartbeat falls outside of the average, it can be an indicator that something’s up. One possible concern is that the baby isn’t getting enough oxygen.

How do you measure the fetal heart rate?

The job of the heart is to provide the body with oxygen. That’s one heck of a brief—so making sure that this organ is in tip-top shape is certainly a serious business. Of course, you want to know that the so-very-young-at-heart inside of you is happily pumping away.

There are two ways to measure fetal heart rate: external and internal:

How do you measure the fetal heart rate?
The job of the heart is to provide the body with oxygen. That’s one heck of a brief—so making sure that this organ is in tip-top shape is certainly a serious business. Of course, you want to know that the so-very-young-at-heart inside of you is happily pumping away.

There are two ways to measure fetal heart rate: external and internal:

  • External, or from the outside of your belly, in. One of the most common methods of external fetal heart rate monitoring is the Doppler ultrasound, which allows your doc to use soundwave technology to transform that tiny fetus heartbeat into something you can see.

    Best advice here is to leave it up to the professionals. While there are fetal Dopplers that are marketed for home use, this is more than a little contentious, both because they can cause false panic and false security. (The FDA advises that Dopplers should be the domain of trained healthcare professionals.)

  • Internal: By going inside through your cervix, your doc is able to attach a wire electrode to the scalp of the fetus that is then connected to the monitor. While this is undoubtedly a bit more uncomfortable, it does give a more accurate reading. This type of monitoring is usually done when your healthcare provider is struggling to get an accurate reading, or when a little extra observation is needed.

Is a heartbeat of 150 a boy or girl?

Turns out, fetal heart rate doesn’t give you any clues as to the birth sex of your baby. So if you’re asking What is the baby’s heart rate for a girl or a boy unfortunately, there’s no reliable evidence that we can tell the difference. If you want to know your baby’s sex, an ultrasound is a better bet, and you may be able to get the intel as early as the first trimester.

Fetal heart rate by week

In an exercise in supreme efficiency, the circulatory system and the fetal heartbeat that is such an important part of it are formed into a functioning network in no time.

Here is the highlights package:

  • 4 weeks: At this point, that tiny heart looks like a blood vessel, already allocated to a very special purpose.
  • 5 weeks: The sweet beat begins. If you have a transvaginal ultrasound at this point, you might just be able to hear it. By this stage, the heart is like a little tree trunk with four branches.
  • 6 weeks: Oh what a difference a week makes—because, by the 6-week mark, that little heart is working busily. Those four little branches have become four chambers and blood is flowing in and out of all of them.
  • 9 to 10 weeks: Okay. This is one happy mama milestone: that teeny tiny heart is fully developed. And thanks to the phenomenal technology that is the Doppler ultrasound, this is typically when you get to hear that fetal heartbeat for the first time. And whoah is that heart beating quickly—about 170 beats per minute. Twice the speed of yours!
  • 20 weeks: It’s time for a full anatomy check—part of which is checking that the heart is operating as it should be. At 20 weeks, heart defects can be detected. Heart defects are one of the more common pregnancy complications, affecting about one in every 100 babies. They mean that, for some reason, the heart and blood vessels have not quite grown as they should. This may make the blood’s journey around the heart and arteries not follow the typical routes. In most cases, the cause of heart defects is unknown.
  • During labor: Your healthcare providers may monitor your baby’s heartbeat while you’re in labor—it’s a good litmus test for how your baby is doing. This kind of monitoring can either be intermittent or continuous and usually depends on the level of risk involved in the pregnancy. Fetal heart rate monitoring is something that you may want to chat to your doc about before the big day, so that you know what your options are.