What is a normal fetal heart rate? How is it measured? And can it tell you about your baby’s birth sex? Read on to find out.
There are very few things pregnancy that are more awe-inspiring than hearing your baby’s heart beat for the first time.
Yup, there’s a living being inside you, a little heart very busy at its job of stealing yours.
So when can you expect to hear this magical sound?
How is the fetal heart beat monitored?
And what is considered “normal”?
They’re already making your heart skip a few beats ‒ why not investigate what’s going on with theirs?
In this article: 📝
- When does a fetus have a heartbeat?
- What is a normal fetal heart rate?
- How do you measure the fetal heart rate?
- What is the heartbeat of a baby girl or boy?
- Fetal heart rate by week
When does a fetus have a heartbeat?
As early as 5 to 6 weeks.
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 doctor 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 normal heart rate in a fetus?
While it varies at different stages of your pregnancy, the average fetal heart rate range is between 110 and 160 beats per minute.
So there’s quite a bit of variability in the fetal heart rate!
If the fetal heartbeat falls outside of the average, it can be an indicator that something’s up.
What is a high fetal heart rate?
A high fetal heart rate (or tachycardia, in medical-speak) is typically anything over 160 beats per minute, but it can be as high as 200 beats per minute.
So what causes a high fetal heart rate?
One possible concern is that the baby isn’t getting enough oxygen.
It could be a developmental blip or something more serious, but your doctor will likely run some more tests to find out.
What is a low fetal heart rate?
A low fetal heart rate is considered anything less than 110 beats per minute.
It’s also known as bradyarrhythmia, in case your doctor uses this term.
But just as with a high fetal heart rate, a low fetal heart rate doesn’t necessarily mean that there’s something wrong with baby.
There are many cases of a low fetal heart rate with a positive outcome ‒ just ask our Peanut community.
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.
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 doctor to use soundwave technology to transform that tiny fetus’s heartbeat into something you can see.
The best advice here is to leave it 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 both false panic and false security.
The FDA advises that Dopplers should be the domain of trained healthcare professionals.
By going inside, through your cervix, your doctor can 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.
What is the heartbeat of a baby girl or boy?
Turns out, contrary to those old wives’ tales you’ve heard, 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 fetal 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’s a breakdown of what you can expect, week-by-week:
4 weeks fetal heart rate
At 4 weeks, that tiny heart looks like a blood vessel, already allocated to a very special purpose.
5 weeks fetal heart rate
At 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 fetal heart rate
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 fetal heart rate
At 9 to 10 weeks, you’ll be reaching 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 woah, is that heart beating quickly ‒ about 170 beats per minute.
Twice the speed of yours!
20 weeks fetal heart rate
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.
Fetal heart rate 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.
So there you have it: all there is to know about your little peanut’s fetal heart rate.
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