Hearing the baby’s heartbeat for the first time is one of the most emotional moments of pregnancy for most parents. It is a magical moment that is generally lived with great enthusiasm as it confirms that the baby is growing healthy and strong. This is why many parents look forward to the first ultrasound to see their little one and hear their heart beat.
However, it is not always possible the first time, sometimes it is necessary to wait a little longer before listening to the baby’s heart. We explain when the baby’s heart begins to beat and what the best times to listen to his heartbeat are.
The growth of the baby’s heart during pregnancy
Did you know that the heart is the first organ to start working in the baby’s body? Like the rest of the organs, it begins to form from the moment of conception.
During the first days, the mesoderm of the cardiac area is formed, which quickly gives rise to two symmetrical structures that hollow out to form the two endocardial tubes. By day 21 of embryonic development, these tubes fuse and form the primitive cardiac tube.
From day 22 of intrauterine life, the primitive cardiac tube continues to develop and gives rise to 5 fundamental parts of the heart: primitive atrium, primitive ventricle, sinus venosus, bulbus cordis and truncus arteriosus.
By day 28 of gestation, the atrioventricular canal divides and forms the right and left parts of the heart. And, in the second month of pregnancy, the heart already has four chambers and beats at a rate of 180 beats per minute.
The fetal heartbeat: The best times to listen baby’s heart
Until very recently it was thought that the baby’s heart did not start working until after the fifth week of gestation, but a recent study carried out at the University of Oxford in conjunction with other universities has shown that this moment actually takes place much earlier. According to these researchers, the baby’s first heartbeat occurs only 16 days after conception.
The problem is that, at this moment, the heartbeat is still very weak and although it is possible to hear it in some cases, the most common is that it cannot be perceived.
On the other hand, a little later, from the sixth week of gestation, the heartbeat is already audible enough and can be heard through a Doppler ultrasound, a technique designed to amplify the sounds that are emitted inside the mother’s womb.
From week 9 or 12 of pregnancy it is already possible to hear the baby’s heart through a traditional ultrasound and, by week 18 or 20 it can be perceived without much effort with a simple stethoscope.
At this time, the fetal heart rate has dropped slightly, although it usually ranges between 110 and 160 beats per minute and tends to be quite irregular, except during the baby’s sleep.
It is worth noting that, sometimes, it is possible to confuse the baby’s heartbeat with that of the mother. An easy way to learn to identify them is to pay attention to your heart rate. In the case of babies, with a much higher heart rate, babies’ heart beats much faster than their mother’s heart.
As the pregnancy progresses, many women often feel their baby’s heart through tiny pulsations. It is a precious experience, which usually comes in those moments when the mother is relaxed and calm.
In these cases, when passing your hand over your belly it is possible not only to notice the baby’s movements but to feel a kind of sound similar to the pulse that is nothing more than the baby’s heartbeat.
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Why can’t I hear my baby’s heart beat?
Sometimes listening to the baby’s heartbeat takes longer than expected without meaning there is a problem with the pregnancy. Factors such as a mother having too thick a layer of abdominal fat or a baby in a complex position are often the most common causes.
However, although this often confuses parents, if the rest of the pregnancy indicators are going from strength to strength, there is really nothing to worry about.
In some cases, there is also the possibility that the gestation date has been miscalculated and the baby is actually in a lower stage of development.
In this type of situation, taking measurements of the fetus through an ultrasound can help determine the exact gestational age. If your pregnancy time is shorter than expected, you will probably have to wait a few more weeks before hearing the baby’s heartbeat for the first time.
Listen to your baby’s heartbeat at home
At present it is not necessary to go to the appointment with the gynecologist to listen to the baby’s heartbeat since there are homemade ultrasound equipments that allows capturing this sound.
These are fetal heartbeat detectors that allow you to listen to the baby’s heart in real time in a simple and fast way. A tool that can be useful for your baby’s grandparents, siblings or uncles can also be part of this experience.
However, it is important to use this type of device wisely. There is no evidence that this type of equipment affects the normal development of pregnancy, but it is known that the use of ultrasound can slightly heat the tissues and, in some cases, promote the appearance of cavitation, that is, the presence of small bubbles in the tissues.
The effects of these reactions on fetal development are unknown; therefore, experts recommend minimizing the use of home ultrasound equipment and, when using them, follow all recommendations.