How and why the fetal heart rate is measured
For any future mother, happiness is to listen to her baby’s heart beating. And, of course, every mother knows that a normal fetal heartbeat is one of the main characteristics of the successful development of pregnancy and an indicator of the vitality of the baby. Therefore, control over the heartbeat should be constant – throughout pregnancy.
What methods of measuring this indicator are used by specialists, and what are the norms of values?
The content of the article:
- Fetal heart rate chart up to 14 weeks gestation
- Fetal heart rate at 5-42 weeks
- Methods for determining fetal heart rate
- How and why is the fetal heart rate measured during labor?
- Fetal bradycardia – causes
- Fetal tachycardia – causes
Fetal heart rate chart in early pregnancy up to 14 weeks
To assess the general condition of the crumbs, the heart rate (approx. – heart rate) is an extremely important criterion, therefore, it is measured at every visit of the expectant mother to the gynecologist.
- The heart of the fetus appears at the 4th week.
- During this period, it is a hollow tube without partitions, which is able to contract already at the 5th week of development…
- And already by 9 weeks The “tube” turns into a four-chambered organ.
An oval “window” remains in the heart for the breathing of the crumbs, so that oxygen is supplied to the baby with the mother’s blood. After giving birth, this window closes.
In the early stages, it is almost impossible to hear the beating of your child’s heart with a stethoscope. Heart rate up to 8-14 weeks the doctor checks exclusively using modern diagnostic methods.
In particular, with the help of ultrasound, which is carried out with a transvaginal (from 5-6 weeks) or with a transabdominal sensor (from 6-7 weeks).
Heart rate table in early pregnancy:
Fetal heart rate (normal)
|80-103 beats / min.|
|155-195 beats / min.|
Of course, these indicators cannot be considered an absolute and 100% sign of the absence of pathologies in a baby – if in doubt about the correctness of development, additional studies are always prescribed.
Fetal heart rate during pregnancy from 15 weeks to 42 weeks
Starting from the 15th week, specialists check the heart rate using modern devices.
The fetal heart rate is considered to be:
Fetal heart rate (normal)
from 15th to 32nd week
|130-160 beats / minute|
|starting from the 33rd week||
All values below 120 or above 160 – serious deviation from the norm. And with an increase in heart rate over 160 beats / minute talk about the initial stage of hypoxia.
Moreover, the heart rate depends not only on the age of the baby, but also on his position, directly on the position in the uterus, on his movements, on the nature of the mother’s abdominal tissue, etc.
Methods for determining heart rate – what devices are used to listen to the heart rate?
- Ultrasound (approx. – transabdominal / transvaginal). With the help of this procedure, the presence of a heart defect or other pathologies in the future crumbs is checked.
- Echocardiography. The method is deeper and more serious, allowing you to analyze the work of a small heart, its structure, as well as the functioning of blood vessels. Usually, this diagnostic method is prescribed by specialists after the 18th and up to the 28th week. For early and late periods, the method is absolutely ineffective: in the 1st trimester, the heart is still too small and not fully formed, and at the end of pregnancy, diagnosis is complicated by a small amount of amniotic fluid. Usually, ECHOKG is prescribed for expectant mothers over 38 years old, or with certain diseases, with which they automatically become a risk group. The method is recognized as the most accurate of the modern ones. In addition, it allows you to record the examination and even enlarge the resulting image for further detailed analysis.
- Auscultation. Or, in simple terms, the use of an obstetric stethoscope. This procedure is carried out for expectant mothers at every doctor’s appointment and during childbirth. With the help of a stethoscope, the specialist determines exactly how the baby is located inside the mother. With a clear listening to the beats of the heart below the mother’s navel, they talk about the head presentation, with the beats in the navel – about the transverse one, and with the heartbeat above the navel – about the pelvic presentation. Also, the tool allows you to determine the nature of heart sounds and the rhythm of its contractions. Thanks to the method, it is possible to timely identify a heart defect or hypoxia. The disadvantage of the method is the lack of its effectiveness in case of a lot / lack of water, with multiple pregnancies or obesity of the mother, as well as with the location of the placenta on the anterior / wall of the uterus.
- Cardiotocography. Indications for this diagnostic method are fever or severe preeclampsia, diabetes mellitus and prematurity, a scar on the uterus, hypoxia or aging of the placenta, arterial hypertension, etc. The CTG method is used from the 32nd week and during childbirth: sensors are fixed on the mother’s stomach , and within an hour, a recording is made, according to the results of which the heart rate is assessed, as well as the reaction of tones to the baby’s movements or contractions. The heart rate recorded by the device is less than 70 beats / min – a reason to suspect an oxygen deficiency or a delay in fetal development. However, with a breech presentation, this indicator is considered the norm.
And how to listen to heart rate crumbs at home?
Every mother would like, being at home, to listen to how the heart of the future toddler beats. And in some cases, you simply cannot do without constant heart rate control.
And it is not necessary to go to your gynecologist for this – there are home methods of “wiretapping”.
- Obstetric stethoscope. True, it will be possible to listen to the baby’s heart with it only after 21-25 weeks. And then – my mother will not be able to hear him, because it is impossible to carry out this procedure on her own – an assistant is needed.
- Fetal doppler. But this ultrasonic device is very effective. It is specially formulated for home use after the 12th week of pregnancy. The device design resembles a CTG apparatus, but with one difference – other dimensions and the inability to create records. Usually headphones are attached to it – for comfortable listening.
How is the fetal heart rate measured and what does it show during labor?
As we found out above, small deviations from the norm in heart rate indicators are not always a reason for panic and suspicion of fetal pathology.
Again, the heart rate rate does not give guarantees that “everything is fine” either.
Why, then, do you need to listen to the heartbeat, and what does it give?
- Establishing the fact that the pregnancy has indeed come. For example, at the earliest possible date – from the 3rd week, when fetal pulsation is already noticeable on the ultrasound scan.
- Analysis of fetal development. Disease and stress are known to speed up or slow down the heart rate. And the heart muscle of the crumbs reacts to changes even faster. An analysis of her work allows us to draw conclusions about the health of the fetus as a whole.
- Monitoring the condition of the fetus during childbirth. Heart rate control during childbirth is extremely important. Doctors must be sure that the baby is coping with the stress, therefore, they monitor the fetal heart activity after each contraction.
In high-risk pregnancies, specialists are required to monitor the heart rate throughout the entire process of childbirth – continuously…
For example, when …
- Hypoxia and IUGR.
- Early or late childbirth.
- Gestosis or severe chronic illness of the mother.
- Stimulation of labor and the use of epidural anesthesia.
- Multiple pregnancy.
In addition to the obstetric stethoscope, the KGT method is mainly used. He most accurately shows all changes during childbirth and writes them down on paper tape.
How is research done?
The expectant mother is attached to her stomach 2 special sensors: one examines the strength and duration of contractions, the other – the fetal heart rate. The sensors are fixed with a special tape and connected to the monitor for recording the study.
During the procedure, the mother usually lies on her left side or on her back.
However, modern equipment is no longer so demanding.
Fetal bradycardia – causes of a rare heartbeat
It happens (usually in the 3rd trimester) that the fetal heart rate is abnormal. The reason may be in external factors, and maybe in the development of pathology.
One of the most common pathologies is recognized as bradycardia, in which the heart rate drops to extremely low values - up to 110 beats / min. and below.
Also, one of the signs of bradycardia is a decrease in the activity of the unborn baby, which is usually noted on CT.
The causes of bradycardia can be different.
Of the main ones:
- Unhealthy lifestyle of the expectant mother. That is, bad habits, the abuse of harmful products, the lack of a proper diet, a sedentary lifestyle.
- Anemia and severe toxicosis.
- Low water and polyhydramnios.
- Stress. Especially those that were transferred in the 1st trimester.
- Taking medications with toxic properties.
- Congenital malformations in a baby.
- Premature placental abruption.
- Chronic diseases of the mother in the respiratory and cardiovascular systems.
- Multiple pregnancy.
- Rhesus conflict in the absence of therapy.
- Umbilical cord entanglement of the fetus.
With the development of bradycardia, immediate intervention is required to eliminate or weaken the harmful effects.
In a complex of therapeutic measures, the following are used:
- Diet, strict daily regimen and rejection of bad habits.
- Compliance with the regimen of physical activity.
- Taking medications containing iron.
- Continuous observation of the fetus.
- A therapy aimed at eliminating exacerbations and symptoms.
Fetal tachycardia – causes of rapid heartbeat
In case of deviation of heart rate values up to 170-220 bpm… talk about tachycardia. This deviation is also cause for alarm.
The reasons can also be different.
First of all, the reasons that directly depend on the mother’s lifestyle:
- Stress and overwork.
- Smoking and medication.
- Abuse of tea, coffee.
Also, fetal tachycardia can cause mom’s health problems:
- Changes in the hormonal composition of the blood and an increase in the level of thyroid hormones.
- Anemia due to iron or vitamin deficiency.
- Large loss of fluid that occurs after vomiting during the period of toxicosis.
- Endocrine pathologies.
- Cardiovascular diseases.
- The presence of injuries accompanied by blood loss.
- Exacerbation of chronic infections.
- Regular colds, bronchitis, etc.
- Rheumatism at the stage of damage to the joints and heart.
As for the causes of embryonic, these include:
- Mother’s multiple births.
- Fetal anemia due to malformed placenta.
- Presence of intrauterine infection.
- Rhesus conflict with mother’s blood.
- Abnormalities in the development of chromosomes.
Diagnosis of tachycardia is carried out using ultrasound and Doppler ultrasound.
Treatment measures include:
- A strict regimen of the day, nutrition and activity.
- A specific diet that includes foods with magnesium and potassium.
- Drug therapy depending on the pathology, its causes, the form of tachycardia and the need for drugs.
Usually, a change in the mother’s lifestyle is enough for the fetal heart rate to return to normal. But, of course, when detecting pathologies in a child, constant medical supervision is necessary, which is not always possible at home.
All information in this article is for educational purposes only, it may not correspond to the specific circumstances of your health, and is not a medical recommendation. The сolady.ru website reminds you that you should never delay or ignore your visit to a doctor!
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