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Fetal CTG is the norm. CTG of the fetus is normal at 36 weeks. How to decipher Fetal CTG
Absolutely every woman during pregnancy experiences how her child develops, whether everything is in order. Today, there are methods that allow a fairly reliable assessment of the condition of the fetus. One such method is cardiotocography (CTG), which reveals the relationship between fetal perturbations and heart rate. From this article you will find out what KTG is, what characteristics it evaluates, what indicators for the CTG of the fetus are the norm, and what affects the results of the study.
What is KTG?
Cardiotocography is based on recording the frequency of fetal heart rate and its changes depending on the influence of external stimuli or fetal activity.
Diagnosis is carried out using two ultrasound sensors, one of which is strengthened on the abdomen of a pregnant woman, having previously determined the area of good hearing of the child's heartbeat.
The results are displayed by the instrument on a paper tape in the form of a graph. The uterine contractions and fetal movements are also displayed there. According to the received data, it is possible to judge, first of all, the state of the nervous system of the baby, about his protective-adaptive reactions. If the CTG of the fetus is normal, it means that the baby feels comfortable, and its development goes according to the terms.
What is required for CTG
Examination of a pregnant woman in an obstetrician-gynecologist's office includes listening to the child's heartbeat with a stethoscope. Deviation from the norm of the heart rate (HR) in greater or lesser side indicates that the child is experiencing discomfort. In this case, the doctor sends the future mother to a more thorough study of the cardiovascular system of the fetus - KTG.
If a pregnant woman has a serious change in her health, it is necessary to carry out CTG as often as possible in order to prevent the occurrence of pathologies in the development of the fetus and take the necessary measures in time.
Features of the study
Assign CTG usually after 32 weeks of pregnancy, because only by this time the maturation of neuromuscular impulses occurs, and the method becomes the most informative.
For example, for the CTG of the fetus, the norm is 33 weeks - the presence on the chart of more than two accelerations. By this time they are caused by the response of the nervous system to fetal movements or to external factors. At earlier times, the accelerations may be related to the conditions of fetal fetal existence, so research can lead to false results.
Also by this time the fetus has a cycle of activity and rest, which is of great importance for this study. When CTG is performed during the fetal rest period, the results will always be positive, even if in fact there is a high degree of hypoxia. That is why the study should be conducted for at least 40 minutes. During this time, the fetus will necessarily intensify the motor activity, which will allow to register the change in heart rate during its movement.
It is very important that a woman feels calm and comfortable during the study. An uncomfortable position or vivid emotions can cause a more active fetal movement, which will lead to false results. Usually during the procedure, the woman sits in a comfortable chair or lies on the couch on her side.
In order to understand how to decipher the CTG of the fetus, we will disassemble in detail, by what parameters it is evaluated.
Basal heart rate
Basal heart rate is the average heart rate of the fetus, calculated for 10-20 minutes. Determine it in the absence of fetal movement between contractions of the uterus without external stimuli, without taking into account the accelerations and decelerations.
Lowering the basal level below the norm (bradycardia) can be due to hypoxia, heart defects of the fetus, as well as low blood pressure of the mother, hypoxemia, prolonged compression of the umbilical cord, the presence of a pregnant woman with a cytomegalovirus infection.
Heart rate variability
This parameter is characterized by the presence of instantaneous oscillations - abnormalities of the heart rate from the basal level. In the analysis of CTG, the amplitude of instantaneous oscillations is usually studied, the nature of which is characterized by low oscillations (deviation is less than three beats / min), medium oscillations (3-6 beats / min), high (amplitude more than 6 beats per minute).
For CTG of the fetus, the norm of 36 weeks is high oscillations, indicating a good state of health of the fetus. The presence of low oscillations indicates pathologies in its development.
Accelerations
Acceleration is a temporary increase in heart rate by at least 15 beats / min in comparison with the basal level and a duration of more than 15 seconds. On the cardiotocogram they look like high denticles. Accelerations are a response to external stimuli, contractions of the uterus, to the movements of the child. Their presence at the CTG of the fetus is the norm.
Deceleration
Deceleration is the reduction in the fetal heart rate by at least 15 beats / min for more than 15 seconds. The chart shows how significant cavities are. Distinguish early, late and variable decelerations. In addition, they are classified in amplitude as light with a decrease in heart rate to 30 beats / min, moderate - 30 - 45 beats / min, and heavy - from 45 beats / min. Decrease in heart rate may occur as a result of impaired placental blood flow, myocardial hypoxia, and compression of the umbilical cord.
CTG of the fetus. Indicator rate
To assess the condition of the fetus, the World Health Organization has developed recommendations that specify the minimum and maximum allowable values for each of the parameters. According to these recommendations, CTG of the fetus (the norm for 33 weeks) should have the following values:
- Basal level of palpitation: 110-160 beats / min.
- Variability of heart rate within 5-25 beats / min.
- Two or more accelerations within 10 minutes.
- Absence of deep decelerations.
It is worth noting that for the CTG of the fetus the norm is 35 weeks or more the same as in 33 weeks.
Assessment of the fetus status by points
Decipher the results of CTG on a 10-point system, evaluating each criterion from 0 to 2 points. For the CTG of the fetus, the norm of 36 weeks, as well as during the entire third trimester, is 9-10 points, if the total score is from 6 to 8, this indicates oxygen hunger (hypoxia) without emergency threats, it is necessary to repeat the CTG procedure in a week;
It should be remembered that even if the CTG of the fetus is 8 points or slightly lower, you do not need to be scared before the time. In this type of research, as well as in many others, there are factors influencing the informative value of the testimony. The results strongly depend, for example, on whether the child is sleeping or awake. Experienced doctors when decoding cardiotocograms take into account factors such as weather conditions, the mood of a pregnant woman, the level of glucose in a woman's blood. If CTG data do not correspond to the norm, the doctor will prescribe an additional examination. Usually cardiotocography is performed twice in the third trimester of pregnancy, but in some cases even more, for example, in multiple pregnancy, high blood pressure, infections, diabetes, unsatisfactory results of ultrasound, bleeding, premature labor.
Possible errors in the interpretation of CTG data
- The child in the womb is in constant motion. Sometimes he can press the head of the umbilical cord, because of which the blood flow in the vessels of the umbilical cord is broken for a short time, which is reflected in the results of CTG. In this case, the cardiotocogram will be pathological in the case of a good fetal condition.
- Sometimes during oxygen starvation , the fetus includes protective reactions: there is a decrease in the oxygen consumption of tissues and an increase in resistance to hypoxia. In such cases, the child suffers, but this is not reflected in the CTG.
- With the development of pathology, the ability of tissues to perceive oxygen at a normal level in the blood can decrease, because of which the fetus does not react, and CTG will be normal, although it suffers from a lack of oxygen.
Given all of the above, it should be understood that CTG of the fetus during pregnancy is a very important method of diagnosis, but to obtain a complete picture of what is happening, CTG data need to be compared with other studies. To date, widely used ultrasound diagnosis and Doppler.
Where can I make CTG of the fetus
CTG is done free of charge in all women's consultations. You can conduct research in private medical centers, but already on a fee basis.
Some future mothers are afraid to conduct all kinds of research during pregnancy, believing that they can harm the health of the baby's future. Cardiotocography is absolutely safe, and it can be done as many times as necessary, without risk to health. In addition, it is painless, does not cause any unpleasant sensations.
We wish you an easy pregnancy and excellent health!
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