Fetal heartbeat is the main indicator of the viability of the unborn child, which reflects its condition and changes as soon as any unfavorable situation occurs. That is why doctors control baby heartbeat throughout pregnancy and especially during childbirth.
Fetal Heart Development
One of the most important indicators of a normally developing pregnancy is baby heartbeat. Throughout pregnancy, and especially during labor, doctors carefully monitor the baby’s heart, as the frequency and nature of the heartbeat reflect the baby’s general condition.
Heart development is a very complex process. The heart of the fetus is laid on the 4th week of pregnancy and looks like a hollow tube. At about the 5th week, the first pulsating contractions appear, and by 8-9 weeks the heart becomes four-chamber (two atria and two ventricles). Due to the fact that the fetus does not breathe independently, but receives oxygen from the mother, the baby’s heart has its own characteristics – the presence of an oval window (the opening between the right and left atria) and the arterial duct (the vessel connecting the aorta and the pulmonary artery). This distinguishes the heart of the fetus from the heart of an adult. These features of the structure of the heart contribute to the fact that oxygen enters all organs and systems of the fetus. After giving birth, the oval window closes and the arterial duct subsides.
Ultrasound, echoCG (echocardiography), auscultation (listening) of the fetus and Cardiotocography are used to assess the fetal heart activity.
Baby Heartbeat at Different Stages of Pregnancy
Although the baby’s blood supply depends entirely on the mother, the blood that came from the placenta in the body is “dispersed” by the baby’s own heart. Therefore, the baby heartbeat is different from the mother’s one.
As the fetus grows, its heart rate is heard more and more clearly. Starting from the sixth week, it can be heard on the ultrasound machine, and from the 20th week the doctor literally hears it – it is enough to attach a stethoscope, and more often – a special auditory tube to the future mother’s abdomen.
“Such a procedure (“ listening to a patient by a doctor ”) is called auscultation, and this is one of the oldest diagnostic methods.
Starting from the third trimester, if the doctor is concerned about the condition of the fetus, the baby heartbeat can be monitored by cardiotocography. This method is used to monitor the state of the baby during prenatal contractions, so we can safely say that most of the mothers are familiar with these three ways to measure the baby heartbeat – ultrasound, auscultation, cardiotocography.
First of all, doctors measure baby heartbeat. It is much higher than that of the mother and depends on the duration of the pregnancy.
|Gestation age||Fetal heart rate|
|6- 8 weeks||110 – 130 beats per minute|
|9-10 weeks||170 – 190 beats per minute|
|11-12 weeks||140 – 170 beats per minute|
|13 week and up to the birth||130 до 160 beats per minute|
Regular Check Outs
Many mothers are worried when the baby’s pulse goes beyond the normal range. But in a fetus, as in an adult, the heartbeat depends on many factors: whether the baby is active or resting, medicines the mother takes, she is calm or not, and finally — by what method the pulse is calculated and where the placenta is located.
The doctor determines not only the pulse rate, but also (which is very important) the rhythm and monotony, whether the baby heartbeat quickens, or suddenly becomes less frequent. Therefore, do not worry if you see a figure in the medical record that goes beyond the normal range. If your doctor thinks there are no problems, you should not worry.
Violation of the Baby Heartbeat
What is considered a pathology of the baby heartbeat? First of all these are serious deviations from the norm, for example, a sharp decrease in the heart rate – below 100 (especially 80) beats per minute.
A decrease in a child’s pulse can be caused by a number of reasons, from extremely rare hereditary bradycardia, when a reduced heart rate is a variant of the norm throughout life, up to cord entanglement, oligoamnios or polyhydramnios. Here is their general list:
- Wrong lifestyle: smoking, drinking alcohol, vitamin deficiency, no outdoor exercise, sedentary lifestyle;
- chronic maternal heart and lung diseases;
- anemia, including first occurring during pregnancy;
- infectious diseases;
- taking certain medications;
- rhesus conflict;
- dehydration due to prolonged toxicosis;
- multiple pregnancy;
- premature detachment of the placenta;
- cord entanglement;
- oligoamnios or polyhydramnios.
Usually, bradycardia, with a rhythmic and non-monotonous pulse, does not threaten the life of the child and can be fixed medically.
When the baby heartbeat is constantly in the range of 170–200 beats per minute, doctors talk about fetal tachycardia. Oddly enough, the causes of its occurrence are for the most part the same as of bradycardia. But in this case, the baby’s body tries to cope with the emergency situation in a different way. Among the reasons are the following:
- dehydration due to prolonged toxicosis;
- taking certain medications;
- vitamin deficiency;
- diseases of the blood vessels and heart of the mother;
- endocrine diseases;
- intrauterine infection;
- mother’s blood loss.
Tachycardia, like bradycardia, does not carry an immediate threat to the life of the fetus – many babies during such pregnancy continue to develop normally. However, in this situation, it is important to consult a doctor, who will notice the deterioration of the situation in time and will correct it, or will offer the mother early delivery.
Monotone Baby Heartbeat
This is another alarming diagnostic sign that often becomes an unpleasant surprise for many mothers. The fact is that the child’s pulse is not constant – so the baby moved, and his heartbeat quickened, he calmed down – it slowed down again. If the baby heartbeat is measured using CTG instruments, the record will look like a series of “hills” and “holes”, or a random set of numbers – 140, 145, 155, 139, etc.
The numbers usually do not change when the baby is deeply asleep – after all, the children in the womb sleep, like all people. Usually the doctor tries to “wake up” the baby – offers the mother to change the posture, walk, etc.
“If time after time the doctor cannot wake up a child, there is an assumption of serious hypoxia – oxygen starvation of the baby.
Usually this is a serious reason for the appointment of an additional examination – ultrasound with Doppler velocimetry. It can be assigned as early as the 20th week.
Congenital Heart Disease of the Child
Separately, it is worthwhile to dwell on such an important moment as congenital cardiac pathologies in a child. The doctor may suspect them if the baby heartbeat does not develop. In this case, the future mother is offered to do an echocardiography, or ultrasound of the heart, only to investigate the heart of the baby, not the mother. This research is usually done at the 18-28 week of pregnancy. Later it may be ineffective due to a decrease in the amount of amniotic fluid. Also, echography offered to women from the “risk group” – those expectant mothers who, for various reasons, are more likely to develop heart disease in the fetus. These are:
- pregnant women over 40;
- pregnant women with diabetes;
- women who suffered severe infectious diseases during pregnancy;
- pregnant women with congenital heart disease;
- pregnant women who have already had children with congenital heart disease;
- if a heart defect was suspected during fetal ultrasound;
- other congenital or genetic diseases, usually associated with heart defects, have been identified.
It is important to identify possible pathologies in a timely manner, as this will help to choose the appropriate mode of delivery, as well as provide specialized assistance to the baby immediately after the birth, without wasting precious minutes.
In any case, we advise you not to neglect medical supervision during pregnancy. Sometimes the pathology of fetal development may be completely invisible to the expectant mother: it seems that everything is in order, the mother feels great, and at the same time, the child suffers from oxygen deficiency. Thus, it is very important to monitor the baby heartbeat. It will allow you to diagnose problems in a timely manner and correct them with the least damage to the child.