At what week does a baby have a heartbeat? When does a fetus have a heartbeat and brain activity? What is the normal rate of a baby's heartbeat? What if there's no heartbeat at 7 weeks?
After a positive result from the pregnancy test, the next thing that excited parents look forward to is hearing their baby's heartbeat. This is one of the most exciting parts of pregnancy, as it confirms that there is indeed life inside a woman's womb.
But when can you really expect to hear the most awaited thumping sound? Learn more about your baby's heartbeat here.
When Can You Hear Baby’s Heartbeat
The foetal heartbeat can be first detected on your 5th to 6th week of pregnancy. Your doctor can point it out to you during your first vaginal ultrasound. At this time, the foetal pole can be seen on the ultrasound also developing an embryo.
Between the 6th and 7th weeks of gestation, your baby's heartbeat is already more pronounced at 90 to 120 beats per minute (bpm). After a couple of weeks, it increases to 140 to 170 bpm.
What is used to detect a baby's heartbeat?
The usual apparatus used to detect a baby's heartbeat is the ultrasound - depending on how far along you are in your pregnancy, it is the vaginal ultrasound or the 2D or 3D abdominal ultrasound.
Transvaginal ultrasound is used in early pregnancy to see if the embryo has formed. Meanwhile, the doctors rely on 3D ultrasound to measure the width, depth and length of the foetus as well as its organs.
Gynaecologists also use a foetal doppler, which uses sound waves to listen to the baby's heartbeat. This is best used during the second trimester of pregnancy. There is also foetal doppler equipment that you can use at home.
It can be quite difficult to hear a baby's heartbeat using only your ears, but some mums swear they have done so, If you want to give it a try, do it in a quiet place, during your second or third trimester, to increase your chances of hearing it.
Changes in Baby’s Heartbeat
Your baby's heartbeat continues to develop as your pregnancy progresses. It starts around 90 to 110 bpm during the first weeks and then increases until it reaches 140 to 170 bpm in the 9th week. It gradually stays at a steady rate of 110 to 160 bpm during the second and third trimesters.
Remember that your baby's heartbeat might change for every prenatal appointment. Foetal heart rate monitoring is very important, especially in high-risk cases where the pregnant woman has gestational diabetes or high blood pressure.
Changes in your baby's heartbeat may indicate foetal distress, which can be a sign that something is wrong.
Can’t Detect Baby’s Heartbeat on Ultrasound
Do not panic if your doctor cannot seem to pinpoint your baby's heartbeat during the first ultrasound. There are some instances that it really happens, and this should not be a cause for alarm right away.
Here are some possible reasons why you cannot hear your baby's heartbeat:
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Do you have the right due date?
Mum, it's important to keep track of your last menstrual period. This will be the basis for calculating your expected date of delivery or your due date. Learning about your due date and having a timeline for pregnancy can help your doctor determine what to expect during pregnancy.
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It's too early
If your pregnancy has not reached its 7th week, it can be that the foetal heartbeat cannot be detected yet. Your doctor will probably advise you to wait for a couple of weeks for a follow-up ultrasound if there are no other symptoms that point to a miscarriage.
As mentioned earlier, the transvaginal ultrasound is a more accurate way of detecting foetal heartbeat during the early stages of pregnancy. You can also wait until your 12th week to have an ultrasound again.
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You used a Doppler to listen to the heartbeat
It's routine for OB-gynaecologists to let the mum hear their baby's heartbeat using a Doppler scan. However, this apparatus is not as accurate during the first trimester as it is just based on sound waves. Your doctor will probably advise you to come back after a couple of weeks to get a much clearer result.
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Position can also be a factor
The mum's position while using the Doppler or ultrasound, as well as the baby's position in the womb, can also affect the loudness and the speed of the baby's heartbeat. Sometimes, simply changing your position or the position of the apparatus can lead to clearer results.
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You have a tilted uterus
The way your uterus is positioned in your pelvis can affect how easy it is for a foetal Doppler to pick up the sound of your baby's heartbeat. Roughly 20 per cent of women have a tilted or retroverted uterus, which means that the uterus is farther away from your abdominal wall than the more common anteverted position.
So not only is the foetal heart further than usual, there could be other things between the uterus and abdominal wall that can make it harder for the Doppler to detect the heart rate.
However, you do not have to worry for as your pregnancy goes along, your uterus will also enlarge and move closer to your abdominal wall. Your baby's heart will grow bigger as well and the heartbeats will be even more pronounced.
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You are overweight
Same in theory with having a tilted uterus, layers of fat may be in between your uterus and abdominal wall, making it hard for the foetal doppler to echo your baby's heartbeat. Meanwhile, during an ultrasound, your doctor or midwife should be able to see the foetal heartbeat by placing the transducer on your lower belly.
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There is no embryo
In certain cases, unfortunately, there is an empty pregnancy sac due to a blighted ovum. This can also be detected through an ultrasound.
What If There's No Heartbeat at 7 Weeks
At 7 weeks of pregnancy, a heartbeat should typically be detectable via ultrasound. However, in some cases, it may not be audible or visible due to various factors, including the positioning of the embryo, the quality of the ultrasound equipment, or the accuracy of dating.
If there's no heartbeat detected at 7 weeks, it's essential not to jump to conclusions immediately. Your healthcare provider may recommend a follow-up ultrasound in a week or two to confirm the situation. In some instances, a heartbeat becomes detectable as the pregnancy progresses.
If, unfortunately, the absence of a heartbeat is confirmed in subsequent ultrasounds, your healthcare provider will discuss the available options, which may include monitoring for a natural miscarriage or considering medical or surgical intervention.
How to Know if You Had a Miscarriage
While it's very common to hear about it on TV or on social media, no expecting parent wants to hear about the possibility of a miscarriage. However, the latest statistics say that 25 per cent of pregnancies in Singapore leads to a miscarriage. It's a sad reality for some women.
A miscarriage is the death of the foetus or failure of pregnancy to develop in the womb before the 20th week of gestation. This usually happens during the first trimester or the 12th week of pregnancy.
Some of the symptoms of a miscarriage include:
- Vaginal bleeding or spotting
- Cramps in the abdomen or lower back
- Signs of pregnancy like nausea and tender breasts will fade
- Blood clots
While some women who experience vaginal bleeding go on to have successful pregnancies, some, unfortunately, have to suffer the loss of their babies. In addition, some women are more at risk of having a miscarriage because of the following factors:
- Age. Teenagers have a greater risk of having a miscarriage than adults. But at the same time, women over the age of 35 are also more at risk.
- Having a history of miscarriage
- Chronic conditions such as high blood pressure or uncontrolled diabetes
- Having uterine or cervical problems
- Smoking, excessive alcohol drinking and use of illegal drugs
- Obesity or being overweight
- Invasive prenatal tests
However, remember that not being able to detect or hear a baby's heartbeat during the ultrasound does not automatically mean that something is wrong with your pregnancy. It can be due to a number of factors and waiting for a few weeks when the foetus is much more developed usually leads to more positive results.
If you have any concerns with your pregnancy, do not hesitate to consult your doctor right away.
This article was written by Anna Santos Villar and translated with permission from theAsianparent Philippines.
Updates by Camille Eusebio
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