Today we’re going to cover everything you ever wanted to know about fetal heart rate in pregnancy and birth.
I will touch on hearing baby’s heartbeat for the first time, how fetal heart rate is monitored during pregnancy and labor, and normal and abnormal fetal heart rate during pregnancy and labor too.
This article is chock-full of lots of good information about your baby’s heart rate during pregnancy and birth, so let’s get a jump on it!
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Hearing baby’s heartbeat for the first time
One of the most exciting and monumental milestones in pregnancy is hearing your baby’s heartbeat for the first time. Those first few weeks of pregnancy are filled with so many conflicting emotions – excitement and possible anxiety mixed with exhaustion and joy.
I know a lot of women struggle with being pregnant but not necessarily feeling pregnant in those early days. Don’t get me wrong, plenty of mamas-to-be are reassured by the morning sickness, tender breasts, and/or sheer exhaustion many experience early on.
But without that growing bump and before you can feel those little baby flutters and kicks, it can be tough for the pregnancy to feel real to some. Hearing baby’s heartbeat for the first time is the exact reassurance that a lot of women need.
When can you hear baby’s heartbeat for the first time?
So, when exactly can you hear baby’s heartbeat for the first time? You can expect your first prenatal visit to be around 8 weeks. If you have any pertinent medical or fertility history your provider might want to see you a bit earlier. Also, don’t panic if you don’t get scheduled until closer to 10 weeks, that is totally normal too.
A heartbeat can typically be detected for the first time between 6-7 weeks. The reason most providers will wait to bring you in closer to 8 or 9 weeks is related to your dating and the potential that it might be off.
The first prenatal visit
Most due dates are calculated by the first day of your last menstrual period (LMP), and then confirmed via ultrasound at your first prenatal visit. Some women have irregular cycles or are unsure of their LMP and therefore aren’t able to provide an estimated date.
At your first prenatal appointment, your provider will not only look for a heartbeat, but will also assess viability and confirm your due date.
In short, baby’s heartbeat can be detected via transvaginal ultrasound as early as 6-7 weeks after conception. If there is no cardiac activity detected at this first visit, your provider should bring you back within 7 days for a repeat ultrasound as your dating might not be accurate.
Related Reading: How to Make the Most of Your First Prenatal Appointment
How is fetal heart rate monitored during pregnancy?
There are a few ways fetal heart rate can be monitored during pregnancy and labor. The main ways are by ultrasound, fetal doppler, external fetal monitoring, and internal fetal monitoring.
Let me explain these a little more in depth:
Ultrasound to monitor fetal heart
Early in pregnancy (typically for the first 12 weeks) you can expect ultrasounds to be done transvaginally. At this early stage, baby is too small to accurately be detected by an abdominal ultrasound. After 12 weeks, all ultrasounds will likely be abdominal.
Fetal doppler
When a fetal doppler can reliably detect baby’s heartbeat depends a little bit on mom’s anatomy and size. It might not be detected as early in someone that has more adipose tissue around their bellies.
But in general, you can expect a fetal doppler to detect baby’s heartbeat sometime between 12-16 weeks. It will be around this time that your provider will use a fetal doppler to auscultate (listen) to baby’s heartbeat at each appointment.
Should I get an at-home baby doppler?
This is something I feel pretty conflicted about. I so get it, mama…I know how hard it is to not worry, especially when you don’t have the reassurance of those kicks and flutters yet.
But the thing about at-home baby dopplers, or really just baby dopplers in general, is that it can be pretty easy to pick up your heart rate instead of baby’s.
A normal fetal heart rate is 110-160 beats per minute whereas a normal, healthy adult heart rate is more in the range of 60-100. Can you imagine the anxiety this would stir up inside of an already anxious mama?
I wouldn’t say that it’s a difficult “skill” to learn, but if you aren’t a trained medical professional then my recommendation would be to stay clear of at-home baby dopplers to prevent any unnecessary anxiety and panic.
External fetal monitoring for heart rate
Further along in pregnancy, you might hear talk of an NST or external fetal monitoring. NST, which stands for non-stress test, is one way of monitoring baby’s heart rate during pregnancy. This is actually how your baby will be monitored during labor!
There are various reasons why your provider might recommend an NST during pregnancy (see below). If you find yourself in a low-risk, uncomplicated pregnancy, then you might not receive an NST at all and your first experience with the external fetal monitors might be when you present to deliver your baby.
Internal fetal monitoring
Internal monitoring is a far less common method of fetal monitoring during pregnancy and labor, but I wanted to briefly touch on it just in case.
The internal device used to monitor your baby’s heart rate is called a fetal scalp electrode (FSE). It’s a little wire that’s placed on baby’s scalp to monitor the heart rate. If we are having difficulty tracing your baby’s heartbeat during labor then your provider might suggest placing an FSE.
To monitor uterine contractions internally, a device called an intrauterine pressure catheter (IUPC) can be placed. This catheter, which must be placed by your provider, is inserted through your vagina, into your uterus, and rests between baby and your uterus.
With an IUPC, we can actually measure the strength of your contractions, in addition to the duration and frequency. With external fetal monitors, we are only able to assess the duration and frequency, not the strength of contractions.
In order for your provider to place internal monitors, your water must be broken. But again, don’t spend too much time focusing on internal fetal monitoring, as it’s a far less common way of monitoring during labor!
Fetal heart rate in pregnancy: What’s normal and what’s not?
I touched on this briefly above – but to reiterate – a normal fetal heart rate in pregnancy is 110-160 beats per minute (bpm). This is for a healthy fetus without any known complications.
What is a normal fetal heart rate?
Sometimes you may briefly hear or see baby’s heart increase beyond 160 bpm before returning to normal. Try not to panic – babies have variations in their heart rates, just like adults.
Think about it like this…what happens when you run up a flight of stairs or when your partner jumps out from behind a door and scares you? Your heart rate temporarily increases before returning to its baseline.
Temporary increases in your baby’s heart rate, known in the labor and delivery world as accelerations, are a very normal and reassuring sign that baby is healthy and well oxygenated.
Abnormal fetal heart rate
If 110-160 beats per minute is considered a normal fetal heart rate then anything outside this range would be considered abnormal. Again, recall what we just discussed above – temporary fluctuations outside of this range are usually nothing to worry about.
The concern is when baby’s heart rate sustains either less than 110 bpm or greater than 160 bpm. Sustains means that it’s not for 30 seconds or even 3 or 4 minutes. We typically consider a baby to have had a change in the baseline of their heart rate after 10 minutes.
What happens if this occurs?
So what does this mean exactly? Does this mean that if your baby’s heart rate is 105 bpm for 20 minutes that we’re automatically going to rush you back to the operating room for an emergency C-section? No, not what this means.
Just as some adults “normal” resting heart rate is less than 90 bpm, athletes for example, some babies also have a slightly higher or lower normal heart rate. In this situation we would take a step back, look at the big picture, do a little digging, and continue monitoring.
What causes high fetal heart rate?
There are times however that an elevated fetal heart rate can be concerning. The most common cause of a high fetal heart rate, at least during labor, is maternal infection.
If at any point during labor your baby’s heart rate starts to climb, the first thing your nurse should do is check your temperature.
Chorioamnionitis (more commonly referred to as chorio) is a bacterial infection that can develop during labor. Most often it occurs in mamas that have had their water broken for 24+ hours.
Other, less common causes of an elevated fetal heart rate include:
- Fetal congenital heart conditions
- Fetal anemia
- Maternal hyperthyroidism
- Maternal substance abuse
- Certain medications
What causes a low fetal heart rate?
There are also things that can cause a fetal heart rate to be low. A low fetal heart rate early in pregnancy can be related to genetic defects or chromosomal abnormalities.
Other potential causes of low fetal heart rates are:
- Certain heart conditions
- Maternal substance use
- Maternal exposure to certain chemicals
If your baby is experiencing any kind of heart rate abnormalities during pregnancy, you can expect your OB provider to refer you to a maternal fetal medicine specialist or an obstetrician that specializes in high-risk pregnancies.
What will my provider recommend if they are concerned about baby’s heart rate?
The plan of action to address an irregular fetal heart rate really depends on what the irregularity is and what the cause might be. As I mentioned above, your OB provider will probably refer you to a high-risk OB specialist.
A maternal-fetal medicine or high-risk specialist is an obstetrician that has special education and training in high-risk pregnancies. In this case, you can expect to continue seeing your OB in conjunction with the high-risk specialist.
Depending on the severity of the abnormality, it might be recommended to change your place of delivery to a hospital that can provide the most appropriate care for your baby after delivery.
Should your baby require surgery or specialized treatment for their heart condition, it is best you deliver at the facility where that will take place.
Baby’s heart rate during birth
You can expect your baby’s heart rate to be monitored during labor and birth. The frequency of monitoring will depend on a few things:
- Your hospital’s policies
- Any interventions
- How baby’s heart rate appears during the monitoring
How is baby’s heart rate monitored in labor?
Most commonly, baby’s heart rate is monitored with an external fetal monitor during labor. One monitor, called a toco, will be applied higher up on your belly and will monitor any contractions you might be having.
The second monitor will be placed somewhere else on your belly and will be used to monitor your baby’s heart rate. Some women are continuously monitored during labor and others are intermittently monitored.
Again, this will depend on the policies at your specific place of delivery, but if you are requiring any kind of interventions (Pitocin, pain medication, induction methods, etc.) or have anything complicating your pregnancy (preterm labor, pre-eclampsia, gestational diabetes, etc.), you can expect to be continuously monitored during labor.
Intermittent monitoring is typically reserved for those women that have low-risk pregnancies, go into labor spontaneously, don’t require any kind of interventions, and whose babies look super happy during monitoring.
I know some people have strong opinions about this topic, making it fairly controversial. Before you put your dukes up, I encourage you to have a conversation with your OB provider to find out more about where they stand and what the policy is at your place of delivery.
Why does baby’s heart rate drop during a contraction?
I always tell my mama’s this right from the beginning, “labor can be stressful for babies and there will probably be times where baby has some dips in their heart rate, requiring us to provide some kind of intervention.”
If I have the time and am able, I prefer to have this conversation with my patients early on in the labor process so that they aren’t as alarmed in the moment.
If you think about what exactly is happening during a contraction then it actually makes good sense why baby’s heart rate might dip some during contractions!
- When you have a contraction, your uterus squeezes your baby, pushing baby’s head down against your cervix
- This series of events helps your cervix to dilate
- Sometimes during this “squeeze”, a baby’s umbilical cord can get compressed, causing a brief and temporary dip in their heart rate
- This is something we call a deceleration in the labor and delivery world
About fetal decelerations
Not to worry, these dips are typically brief, temporary, and not super concerning. There are also some pretty non-invasive interventions that your medical team can do:
- Change your position
- Give you some IV fluid
- Administer oxygen, if needed to help correct the deceleration
The good news? These interventions are effective the majority of the time! Occasionally, these interventions are not effective and we are unable to get baby’s heart rate back up.
In this case, depending on the length and severity of the deceleration, your provider might discuss the need for more invasive interventions, such as an amnioinfusion or C-section.
This doesn’t commonly happen so don’t stress over this too much. I just wanted to put it on your radar so that you aren’t completely blindsided if it happens to you.
What happens if baby’s heart rate during labor is concerning?
As I just discussed, it can be pretty common for your baby to have some brief, small dips in their heart rate at some point during labor. Labor can be stressful for baby…remember how we talked about them getting that big squeeze?
The majority of time the dips are benign and don’t pose much, if any, concern. Sometimes, however, the dips are more concerning if they become frequent, deep, or are unable to be corrected with interventions.
There are some slightly more invasive interventions that can be done by your provider to help correct a concerning fetal heart rate.
But at the end of the day, if we are not successful getting baby’s heart rate back up, then a C-section would be the safest mode of delivery.
The C-section might be performed emergently, urgently, or just routinely depending on the situation. The OB provider is typically the one to dictate how urgent the procedure will be.
Our ultimate goal as your labor and delivery team is “healthy mama, healthy baby, healthy mind”!
Wrapping up
So, how are you feeling about fetal heart rate in pregnancy and birth? I hope this article has supplied you with all the information you need to feel confident about this!
I’m all about providing knowledge to empower and educate mamas to help them have an even better (and safer!) birth experience.
This is why I put together this article and lots of other pregnancy, labor, and birth resources, some of which you can check out below!
- Mommy Labor Nurse Online Birth Courses
- Scared of Giving Birth for the First Time? The Top 6 Labor Fears Answered
- Prepare for Labor and Birth: 10 Things Not to Skip from an L&D Nurse
- Are Birthing Classes Necessary? Thoughts from an L&D Nurse
