When Does A Fetus Develop A Heartbeat?


This is a question most pregnant women tend to ask, especially those who are pregnant for the first time, as they and their husbands want to feel the heartbeat and the baby kicking often and on. However, the question is a straightforward one and does also have a straightforward answer.

The answer to this curious question is three weeks and one day. Although we may choose to learn more about heartbeats which may perhaps be an interesting subject to talk about. To satisfy the curiosity of pregnant women, we may also state that the heart beats over 54 million times between the periods of fertilization and the birth of the child. 

Hence, if you have the privilege to stay for about 80 years on this planet, it is calculated that your heart should beat approximately 3.2 billion more times, and if you live for a few more years, then you could be averaging a total of 3.5 billion heartbeats. That’s quite a huge number, you may want to say, but apparently, that is a correct calculation of your heartbeat.

But we will concern ourselves with the knowledge of a fetus’s heart development which should interest pregnant women more than the number of times their hearts may beat if they live up to 80 years. The knowledge that they are expecting a baby gets them excited for every woman as they get to know this via ultrasound of the baby inside the womb. Usually, the image includes a little heart, and the rhythmic palpitation of that heart is ultra-important for the wellbeing of the baby, thus making a baby’s heartbeat an interesting and important topic of discus. 

Interestingly, modern medicine has found a way for doctors to collect important information about the baby’s heartbeat as well as the baby’s heart condition; hence, they can easily detect congenital heart conditions at an early stage as well as attempt to nip it in the bud before it grows out of proportion.

Overview Of The Development Of A Fetal Heartbeat

The heart typically starts its development in tube-shape and grows to develop chambers as well as other features with time; hence, the heart resembles a normal heart by the time the child is born. However, the fetus’s heart starts to form on the third week or on the 22nd day, which is the first day of the fourth week, and this is specifically when the heart begins to beat.

However, at this stage, getting to hear the heartbeat is cumbersome and near impossible because, at this stage, the heartbeat is too soft to be heard via conventional stethoscopes. However, the doctor could hear the heartbeat with the aid of the fetoscope, which is more sensitive and less conventional compared to the stethoscope. It is also important to state that even with the aid of the fetoscope, getting to hear the heartbeat’s sound is still challenging when you factor in all the internal noises that occur within the mother’s body and the activities of the fetus itself.

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The fetus’s heart chamber begins to develop by the fifth week. Even though the heartbeat is still very soft to be heard by a conventional stethoscope at this stage but it becomes a lot easier to detect via specialized equipment. By the sixth week, the heartbeat increases to an average of 100 to 150 beats per minute. At this stage, the heart can be spotted beating via an ultrasound monitor, and by the eighth week of development, the heart will have gained stride, which is indicated by the heart’s steady rhythm.

Interestingly, at this stage, the fetus’s heart beats even faster than that of its mother. In the tenth week of development, the fetus’s heartbeat rate increases to about 170 beats per minute before ultimately slowing down to a steady rate of 130 beats per minute by the time the baby is born. However, with all the strides medicine has made in recent years, there is still a puzzle that is begging to be solved, a few questions still begging for answers.

These questions are, how does the heart begin to beat? And what powers it on? And what controls the rhythm? Answers to these questions may take time to arrive. Still, scientists generally agree that finding answers to these questions will go a long way in helping medical science understand heart defects better than they do now and develop effective treatments for the defects.

What Devices Are Used To Measure Fetal Heartbeat?

There is various equipment used to measure the heartbeat of a fetus; however, each device is appropriate for different developmental stages and designed to measure just different aspects of heartbeats, ranging from the measurement of heart rhythm to the measurement of the heart rate.

The Fetal Doppler

The fetal Doppler is a device that employs the use of sound waves to map internal organs; this is done by moving the device to the surface of the mother’s womb to enable it to send sound waves into her body. The sound waves significantly rebound off the internal organs and form a pattern on the screen used to monitor the measurement.

However, it is important to state that the fetal Doppler does not in any way display images on the monitor screen. Thus making it an ultrasound transducer that is used only to detect a fetal heartbeat.

Transvaginal Ultrasound

The fetal Doppler is employed between the third week and fifth week of fetal development, but after six weeks of pregnancy, the fetal Doppler is not-longer needed. At this stage, a different device is required, and it is called the transvaginal ultrasound. The transvaginal ultrasound detects heartbeats by inserting a probe via the mother’s vagina, which ultimately sends sound waves rebounding off the walls of the mother’s uterus, and then these rebounding waves are then unilaterally converted to images; hence, the fetus can be eventually monitored as well as the determination of the stride made by the pregnancy via the transvaginal ultrasound.


With the two methods listed above, there are chances that the heart rate, as well as the heart rhythm, may not be as accurate as stated. The most accurate means for checking a baby’s heartbeat is using an electrode that is used before the baby is given birth. The electrode is in effect used by inserting it into the mother’s cervix.

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It is important to attach the electrode to the baby’s head as well as connect it to a monitor to enable the doctor to make the necessary checks.

When You Don’t Hear Your Baby’s Heartbeat

There is the chance that you might not get to hear your baby’s heartbeat at your first ultrasound. Many factors may be responsible for that, and we will like to iterate that at the early stage of fetal development, the heartbeat is too soft to be heard via a conventional stethoscope. However, a few special devices can enable mothers to hear the heartbeat of the fetus inside them interestingly, if you don’t get to hear your baby’s heartbeat during your first ultrasound scheduled with the doctor or ultrasound technician. Well, that doesn’t necessarily imply that something may be wrong. 

The reason could be that your pregnancy is still at an early stage and the baby’s heartbeat is still too soft to be detected by conventional devices. A few more reasons why you may not hear fetal heartbeat includes 

  • When you have a tipped uterus, a tipped uterus is also referred to as a retroverted uterus, and that implies the uterus that arcs in a backward position at the cervix as an alternative to a forward position.
  • Having a large abdomen; another obvious reason you may not get to hear the baby’s heartbeat during the first ultrasound is due to the effect of a large abdomen.

If no heartbeat is detected, then it is imperative that your doctor should check your fetal measurement or reschedule for another ultrasound. When the embryo has acquired a crown-rump length greater than five millimeters, then your doctor may be greatly concerned at this stage. If there is no gestational sac after six weeks of fetal development, then your doctor may ultimately request that you carry out a blood test to confirm the pregnancy.

Can You Hear Your Baby’s Heartbeat With Your Ear?

Detecting a fetal heartbeat with the human ear may be the most cumbersome task known to man, that is, if it is not impossible. However, some pregnant women claim they hear the sound of their baby’s heartbeat, but the veracity of their claim remains vague, even though it may be possible or achievable in a quiet room.


Pregnant women generally want to hear the sound of their baby’s heartbeat, and this often opens up the question of when does a fetus develop a heartbeat? An interesting question for expecting mothers; however, the answer to the question is detailed in this article, and we hope that you find it helpful.

When does a fetus develop a heartbeat is perhaps the most important question asked by pregnant, especially the ones who are pregnant for the first time, as they and their husbands want to feel the heartbeat and the baby kicking often and on. However, the question is a straightforward one and has a straightforward answer, and we believe that this article has done a lot to answer the question and prepare them for what lay ahead.

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