Ktg data. What is cardiotocography (CTG) during pregnancy, and how is it done? Planned KTG calendar

CTG (cardiotocography) is a method for studying the fetal heartbeat and uterine contractions in pregnant women, in which all these records are recorded on a special tape. The child's heart rate will depend on several factors such as the time of day and the presence of risk factors.

In what cases is CTG prescribed?

How are the final indicators of CTG deciphered?
The decoding of the final ones is carried out by a specialist, taking into account such data as: fetal heart rate variability, basal rhythm, acceleration, deceleration and fetal motor activity. Such indicators, at the end of the survey, are displayed on the tape, and have the form of graphs, different in form. So, let's take a closer look at the above indicators:
1. 1. Variability (or amplitude) refers to violations of the frequency and regularity of contractile movements of the rhythm and amplitude of the heart, which are based on the results of the basal rhythm. If no pathology of fetal development is observed, heart rate indicators should not be uniform, this can be clearly seen with the help of visualization by a constant change of numerical indicators on the monitor during a CTG examination. Changes within the normal range can range from 5-30 beats per minute.
  2. The basal rhythm indicates the average heart rate of the baby. Indicators of the norm are the heartbeat from 110 to 160 beats per minute during the calmness of the fetus and woman. If the child is actively moving, the heart rate will keep from 130 to 180 beats in the course of one minute. Indicators of the basal rhythm within the normal range mean the absence of a hypoxic state of the fetus. In cases where the indicators are below the norm or above, it is considered that there is a hypoxic condition that adversely affects the nervous system of the baby, which is in an underdeveloped state.
  3. By acceleration is meant an increased amount of heartbeat, compared to the level of basal rate indicators. Acceleration indicators are reproduced on the cardiotocogram in the form of cloves, the norm is from two to three times in 10-20 minutes. Perhaps a small increase in frequency up to four times in 30-40 minutes. Pathology is considered if acceleration is completely absent for a period of 30-40 minutes.
  4. Deceleration is a decrease in heart rate compared to the degree of basal heart rate. Deceleration indicators are in the form of dips or otherwise negative teeth. Within the limits of the normal functioning of the fetus, these indicators should be completely absent or very slightly manifested in depth and duration, and are very rare. After 20-30 minutes of CTG examination, with the manifestation of deceleration, there are suspicions that the condition of the unborn baby will worsen. Of great concern in the development of the fetus is the repeated and varied manifestation of deceleration during the entire examination. This can be a signal of the presence of decompensated stress in the fetus.
The Importance of Fetal Health Indicators (PSP)
After the graphical results of the CTG study are ready, the specialist determines the value of the indicators of the fetal condition. For the normal development of the child, these values will be less than 1. When the PSP values are from one to two, this indicates that the condition of the fetus begins to deteriorate and some unfavorable changes appear.

When the PSP is over three, this means that the fetus is in critical condition. But with only such data, the specialist cannot make any decisions; first, the full history of the course of pregnancy will be considered.

You need to understand that not only pathological processes in the development of the baby can cause deviations from the norm, it can also be some conditions of the pregnant woman and the baby that do not depend on violations (for example, elevated temperature in a pregnant woman or, if the baby is in a state of sleep).

What CTG scores are considered normal during CTG, is it considered a pathology?

The results of cardiotocography are evaluated according to a special Fisher scoring scale - assigning 0-2 points to each of the above indicators. Then the scores are summed up and a general conclusion is made about the presence or absence of pathological changes. The result of CTG from 1 to 5 points indicates an unfavorable prognosis - the development of hypoxia in the fetus, a 6 point value may indicate incipient oxygen deficiency.

What does a CTG score of 7 points mean in conclusion?

CTG 7 points - this assessment is considered an indicator of the onset of fetal oxygen deficiency. In this condition, the specialist prescribes appropriate treatment in order to avoid the occurrence of hypoxia, as well as to improve the condition of the baby, if any. With a score of 7 points at week 32, therapeutic measures begin to be carried out without slowing down. A doctor who monitors the course of pregnancy can urgently send a woman for inpatient treatment or limit herself to droppers at a day hospital.

During the light stage of oxygen starvation, more frequent and prolonged exposure to fresh air is dispensed with, weather permitting. Or taking medication to prevent this condition.

Even if, after deciphering the CTG examination, the specialist determines the result at 7 points, which are an alarming sign, you should not panic, because modern medicine can help the unborn baby get rid of this condition.

If pathological processes in the baby are detected, which are a reaction to uterine contractions, it is urgent to consult a gynecologist with the results of the study. After evaluating the results, the specialist will be able to prescribe competent treatment, as well as send for a second CTG.

The value of the CTG score 8 points

Many expectant mothers are interested in the question of 8 CTG scores, are these indicators a cause for concern? CTG 8 points shows the lower limit of the norm, and this condition of the fetus usually does not require any therapeutic measures or hospitalization.

What is the significance of scores of 9 and 10?

A score of 9 and 10 is considered normal. These indicators can mean one thing, that the development of the fetus is going well, without the development of pathologies. A score of 10 points indicates that the condition of the unborn baby is within the normal range.

What pathological processes can be revealed in the study of CTG?

How to perceive the results of CTG? Relying only on the obtained CTG data, it is impossible to finally determine the diagnosis, since pathological deviations from the 10-point norm can be a temporary condition in response to some external stimulus. This technique is easy to perform and will help to identify deviations from the norm in the development of the fetus without any special costs.

The CTG method will help to identify the following pathologies:

When abnormalities were detected during the decoding of CTG, the doctor prescribes an ultrasound scan, as well. If required, the pregnant woman is prescribed treatment and repeated CTG.

Absolutely every woman during pregnancy worries about how her child develops, whether everything is in order. Today, there are methods that allow you to fairly reliably assess the condition of the fetus. One of these methods is cardiotocography (CTG), which reveals the relationship between fetal movements and heart rate. From this article you will learn what CTG is, by what characteristics it is evaluated, what indicators for are the norm, and what affects the results of the study.

What is CTG

Cardiotocography is based on recording the frequency and its changes depending on the influence of external stimuli or fetal activity.

Diagnosis is carried out using two ultrasonic sensors, one of which is fixed on the belly of a pregnant woman, having previously determined the area of good audibility of the child's heartbeat.

It is designed to record the heart activity of the fetus. The sensor perceives the ultrasonic signal reflected from the child's heart, which is further converted by the electronic system into an instantaneous heart rate. The second sensor is fixed on the abdomen in the fundus of the uterus. It registers uterine contractions. To improve the passage of ultrasonic waves, the sensors are treated with a special gel. Also, modern devices are equipped with a remote control, by pressing the button of which, a pregnant woman can note the movements of the fetus.

The results are displayed by the device on a paper tape in the form of a graph. It also displays uterine contractions and fetal movements. According to the data obtained, it is possible to judge, first of all, the state of the nervous system of the baby, his protective and adaptive reactions. If the indicators of fetal CTG are the norm, then the baby feels comfortable, and his development is proceeding according to the timing.

Why is CTG needed?

Examination of a pregnant woman in the office of an obstetrician-gynecologist includes listening to the baby's heartbeat with a stethoscope. A deviation from up or down indicates that the child is experiencing discomfort. In this case, the doctor sends the expectant mother for a more thorough study of the functioning of the fetal cardiovascular system - CTG.

There is a clear relationship between the well-being of a pregnant woman and the condition of the fetus. So, if the pregnancy proceeded calmly, without intrauterine infection, the threat of interruption, preeclampsia, then the results of CTG are likely to be normal. If, with good health of the pregnant woman, suspicious results of CTG are observed, then it is necessary to re-examine after a week.

If serious changes in the state of health are found in a pregnant woman, then it is necessary to conduct CTG as often as possible in order to prevent the occurrence of pathologies in time and take the necessary measures.

Features of the study

CTG is usually prescribed after the 32nd week of pregnancy, since only by this time does the maturation of neuromuscular impulses occur, and the method becomes the most informative.

For example, for fetal CTG, the norm is 33 weeks - the presence of more than two accelerations on the chart. By this time, they are caused by the response of the nervous system to the movements of the fetus or to external factors. At earlier periods, acceleration may be associated with the conditions of intrauterine existence of the fetus, so the study may 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 conducting CTG during the rest period of the fetus, the results will always be positive, even if there is actually a high degree of hypoxia. That is why the study should be carried out for at least 40 minutes. During this time, the fetus will definitely increase motor activity, which will allow you to register a change in heart rate during its movement.

It is very important that the woman feels calm and comfortable during the examination. Uncomfortable position or strong emotions can cause more active movement of the fetus, 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 analyze in detail by what parameters it is evaluated.

Basal heart rate

Basal heart rate is the average fetal heart rate calculated over 10-20 minutes. It is determined in the absence of fetal movement between uterine contractions without external stimuli, without taking into account accelerations and decelerations.

When conducting fetal CTG, the BHR rate is 110-160 beats per minute. Tachycardia, that is, an excess of the normal basal heart rate, can be observed with anemia, malformations and insufficiency of fetal heart function, as well as with a feverish state of a pregnant woman, the presence of an intrauterine infection, and increased thyroid function. Taking drugs that have a cardiac stimulating effect can lead to an increase in the fetal heart rate.

A decrease in the basal level below normal (bradycardia) may be due to hypoxia, fetal heart defects, as well as low maternal blood pressure, hypoxemia, prolonged umbilical cord compression, and the presence of a cytomegalovirus infection in a pregnant woman.

Heart rate variability

This parameter is characterized by the presence of instantaneous oscillations - deviations of heart rate from the basal level. When analyzing CTG, the amplitude of instantaneous oscillations is usually studied, according to the nature of which low oscillations are distinguished (deviation is less than three beats / min), medium (3-6 beats / min), high (amplitude more than 6 beats / min).

For fetal CTG, the norm is 36 weeks - high oscillations, indicating good health of the fetus. The presence of low oscillations indicates pathologies in its development.

Particular attention in the analysis of cardiotocograms is paid to slow oscillations. Depending on their amplitude, a monotonous type is distinguished, which is characterized by a low amplitude of oscillations (from 0 to 5 beats / min), a transitional type with an amplitude of 6 to 10 beats / min, a wavy type (from 11 to 25 beats / min) and a jumping type. (amplitude above 25 beats / min). An increase in the amplitude of oscillations may be associated with moderate hypoxia of the fetus, as well as with the influence of external stimuli that stimulate its nervous system. A decrease in the amplitude of oscillations can be caused by severe hypoxia, which leads to inhibition of the function of the fetal nervous system, by the use of narcotic drugs, tranquilizers.

Accelerations

Acceleration is a temporary increase in heart rate of at least 15 beats / min compared to the basal level and a duration of more than 15 seconds. On a cardiotocogram, they look like tall teeth. Accelerations are a response to external stimuli, uterine contractions, and baby movements. Their presence on the CTG of the fetus is the norm.

Decelerations

Deceleration is a decrease in the fetal heart rate by at least 15 beats / min for more than 15 seconds. The graph is presented as significant depressions. There are early, late and variable decelerations. In addition, they are classified by amplitude as light with a decrease in heart rate up to 30 beats / min, moderate - 30 - 45 beats / min, and severe - from 45 beats / min. A decrease in heart rate may occur due to impaired placental blood flow, squeezing the umbilical cord.

Fetal CTG. Norm of indicators

To assess the condition of the fetus, the World Health Organization has developed recommendations that indicate the minimum and maximum allowable values for each of the parameters. According to these recommendations, fetal CTG (normal for 33 weeks) should have the following values:

Basal heart rate: 110-160 bpm.
Heart rate variability within 5-25 beats / min.
Two or more accelerations within 10 minutes.
No deep decelerations.

It is worth noting that for fetal CTG, the norm of 35 weeks or more is the same as at 33 weeks.

Assessment of the state of the fetus by points

Decipher the results of CTG on a 10-point system, evaluating each criterion from 0 to 2 points. For CTG of the fetus, the norm of 36 weeks, as well as during the entire third trimester, is 9-10 points, if the total number of points is from 6 to 8, this indicates oxygen starvation (hypoxia) without emergency threats, it is necessary to repeat the CTG procedure in a week;

if 5 points or less - it means that the child is experiencing severe oxygen starvation, which can lead to serious neurological problems, urgent action is needed.

It must be remembered that even if the CTG of the fetus is 8 points or slightly lower, there is no need to be scared ahead of time. In this type of research, as well as in many others, there are factors that affect the information content of the testimony. The results are highly dependent, for example, on whether the child is sleeping or awake. Experienced doctors, when deciphering cardiotocograms, also take into account such factors as weather conditions, the mood of a pregnant woman, and the level of glucose in a woman's blood. If the CTG data does not correspond to the norm, then the doctor will prescribe an additional examination. Usually, cardiotocography is performed twice in the third trimester of pregnancy, but in some cases more, for example, with multiple pregnancies, high blood pressure, infections, diabetes, poor ultrasound results, bleeding, premature contractions.

Possible errors in the interpretation of CTG data

The baby in the womb is in constant motion. Sometimes he can press the umbilical cord with his head, because of which the blood flow in the vessels of the umbilical cord is disturbed for a short time, which is reflected in the results of CTG. In this case, the cardiotocogram will have a pathological character with a good condition of the fetus.
Sometimes during the fetus, protective reactions are activated: there is a decrease in oxygen consumption by tissues and an increase in resistance to hypoxia. In such cases, the child suffers, but this does not affect the CTG.
With the development of pathology, the ability of tissues to perceive oxygen at its normal content in the blood may decrease, due to which the fetus does not have any reaction, and CTG will be normal, although it suffers from a lack of oxygen.

Given all of the above, you need to understand that fetal CTG during pregnancy is a very important diagnostic method, but in order to get a complete picture of what is happening, CTG data must be compared with data from other studies. To date, ultrasound diagnostics and dopplerometry are widely used.

Where can I do a fetal CTG

CTG is done free of charge in all antenatal clinics. You can conduct a study in private medical centers, but on a paid basis.

In maternity hospitals, cardiotocography is also performed during childbirth. This helps to assess the well-being of the child in childbirth and uterine contractions, to check the effectiveness of the treatment and tactics of childbirth.

Some expectant mothers are afraid to conduct various kinds of research during pregnancy, believing that they can harm the health of the unborn baby. Cardiotocography is absolutely safe, and you can do it as many times as necessary, without risk to health. In addition, it is painless, does not cause any discomfort.

We wish you an easy pregnancy and excellent health!

According to analyzes and external signs, it is difficult to determine the condition of the baby in the womb. The most effective method is cardiotocography. A special apparatus consistently captures the child's heart rate. The values are compared with periods of uterine wall contractions. This is the most informative indicator of the condition of the fetus. CTG during pregnancy is often done to identify possible pathologies of the fetal cardiovascular system. The method is used even during contractions, during childbirth.

What else is CTG done for? Where and how is the diagnosis carried out? Are there any risks for the baby? How to decrypt data? What result of CTG means developmental pathology? What to do with doubtful evidence?

CTG: what is it?

The technique is based on the Doppler effect. The CTG apparatus has strain gauges. They fix the frequency of the basal rhythm, while assessing the activity of the uterus. Special monitors display information about the strength of contractions of the uterine walls, the cycles of the child's heart, then a paper tape is printed. It shows two curved lines of the studied data. Their combination is an indicator of the well-being of the baby.

A non-stress test for the fetus is done routinely. Mandatory CTG for a child needs to be done for a period of 28-29 weeks. By this period, the fetus has developed enough for specialists to track the most important indicators of its condition and evaluate the relationship between heart rate and physical activity.

Fetal CTG is external and internal. The latter method is rarely used, only during childbirth, if the cervix is sufficiently open and the integrity of the bladder is broken. Fetal cardiotocography is performed using electrodes inserted into the vagina. A catheter is used to record information about the tone of the uterus. The external method is widely used in the last trimester and during childbirth.

Why is a test done during pregnancy?

When conducting CTG, a lack of oxygen (hypoxia), anemia, and congenital heart pathologies are detected. By indirect signs, it is possible to diagnose oligohydramnios, fetoplacental insufficiency. Research methods such as ultrasound and dopplerography show the state of the placenta and blood vessels. However, the information obtained does not provide complete information about the sufficiency of providing the baby with oxygen.

Hypoxia causes a delay in the development of the baby. A child who has experienced oxygen starvation in the mother's womb will not be able to independently pass through the birth canal. At an early age, these babies have serious health problems.

Why else is there a survey? CTG during pregnancy evaluates the possible pathological condition of the mother and the child as a whole. By the movements of the baby, it is determined whether his body is prepared for physical exertion, the regularity and frequency of myocardial contractions, and the activity of the child are assessed.

Violation of the functioning of the uterus is a threat to normal gestation. Based on the results of the study, the doctor evaluates the method and timing of delivery. If pathological deviations in development are detected, the examination allows the necessary therapy to be carried out in time.

From what week can CTG be performed?

Cardiotocography must be done when the baby has a mechanism for regulating myocardial contraction. This happens at 28 weeks of gestation. After 32 weeks, the examination is carried out weekly - at 33, 34, 35, 36, 37 and 38 weeks, then - according to the presence of indications.

The heart of the fetus begins to beat a month after conception. Muscle contractions are still generated by cells. The rhythm of the heart in the first months is not regulated by the nervous system. He kicks back impulsively. By the middle of pregnancy, the baby's heart rate slows down. Muscle fibers begin to receive signals from the vagus nerve, acting on the principles of the functioning of the parasympathetic nervous system. From the 20th week, the rhythm can be listened to, therefore, if there are indications in the early stages, CTG is performed. Pathological deviations in the rhythm at this time can already be determined.

From the 28th week, the baby's motor activity and wakefulness affect the heartbeat. For this reason, CTG is most informative in the third trimester of gestation. With a normal pregnancy, cardiotocography is done weekly from 32 weeks.

With the development of hypoxia - the study is carried out daily. Sometimes an emergency birth may be necessary.

How to properly prepare for the procedure?

Special preparation before the examination is not required. It is not recommended to do the procedure on an empty and overloaded stomach. You need to eat 1.5-2 hours before the test. You can eat something sweet during the procedure. This stimulates the baby's motor activity. How should a pregnant woman prepare? Be sure to go to the restroom, empty the intestines and bladder. CTG takes up to 40 minutes, you can not be distracted and get up. A woman should be relaxed, calm, not distracted by external stimuli.

Before the CTG procedure, a woman needs to sleep. After arriving at the consultation, you should rest for a while to restore breathing and heart rhythm. Mom's emotions affect the child's activity. Overexertion and stress should be avoided. Some experts do not recommend taking sedatives and painkillers for a day.

Algorithm for performing cardiotocography

CTG during pregnancy is done mainly by an indirect method. Two sensors are attached to the abdomen, fixed with straps. They are arranged in such a way that one fixes the work of the uterus, the second - the heartbeat of the child. The woman lies on her back. In the last weeks, the procedure is done in a half-sitting or lying position (on the left side). This position does not allow compression of the inferior vena cava.

The installation site of the first sensor is determined by palpation, as a result of which the doctor understands where the baby's back is turned, what position the baby has taken in the womb. The second sensor is installed where the bottom of the uterus is located.

The number of movements of the child is recorded directly by the woman. To do this, she presses the button when she feels a stir. How long does the examination take? The minimum recording time is 20 minutes. So much is needed to fix the average heart rate with at least two periods of activity (15 seconds each). The maximum time for a CTG examination is 40 minutes.

Is it harmful for the child?

The examination is considered absolutely safe. CTG is a non-stress test that gives a sufficient amount of information to the doctor. If pathological deviations from normal values are detected, additional fetal diagnostics are prescribed, and then a treatment regimen is determined.

There are no contraindications to the examination. The process is painless, does not cause any discomfort to the mother and child. The only inconvenience is the need to be in the same position for about half an hour. After the diagnosis, women admit that it is even pleasant to lie down and hear the baby's heart rhythm.

Deciphering the results

The data is printed on a paper tape in the form of curved lines. The doctor is engaged in the interpretation, evaluating the possible deviations of the graphs from the norm. Each parameter and final result is evaluated in points. Decoding includes the analysis of the following indicators:

basal rhythm;
variability;
number of movements;
acceleration (increased heart rate);
deceleration (slowdown of the heart).

The basal rhythm is calculated as the average number of myocardial contractions. The amplitude of fluctuations with which the value deviates from the mean is called variability. Acceleration and deceleration (how many times in one minute the beating of the heart muscle accelerates and slows down) with CTG is also estimated from the initial averaged rhythm.

The norm of indicators according to WHO

In a calm state of the child and mother, the normal value of the basal rhythm is from 110 to 160 beats per minute. During periods of activity of the baby - from 140 to 190. A slow or too frequent heartbeat means a lack of oxygen. This condition negatively affects the nervous system of the child.

The acceleration and deceleration of the heart is estimated relative to the average value. The frequency of myocardial contractions is unstable. Normal variability is from 5 to 25 beats. The heartbeat should not be lower than the specified value.

Fisher scale

The ten-point rating system was developed by an American obstetrician-gynecologist. Each PSP is evaluated according to Fisher 0, 1 or 2 points. According to the total score, the CTG is deciphered.

The resulting score is interpreted as follows:

8-10 - the norm, the baby feels good;
6-7 - oxygen starvation begins, in this case additional diagnostics are mandatory;
1-5 - critical condition, hypoxia, emergency delivery is indicated.

Krebs score

In this interpretation, another indicator is considered - the number of active fetal movements against the background of a calm state. The activity criterion is evaluated over a period of half a minute. More than 5 recorded movements during the study period are estimated at 2 points. From 1 to 4 - 1 point is assigned. In the absence of activity, points are not awarded.

In general, the Krebs scale is a 12-point system. Getting from 9 to 12 points means a good result, the child's well-being is normal. A score of 0-8 is a warning sign. Additional examinations, urgent measures will be required to save the child.

Dawes-Redman Decoding Criteria

The scale is designed for automatic devices. The results of the recording are evaluated without the participation of a doctor. The calculation algorithm according to the Dose-Redman system takes into account the same initial data as in the evaluation by a specialist. STV variability is calculated. The method is used during pregnancy, but it is not used when childbirth has begun.

Evaluation options, taking into account the Dawes-Redman criteria:

6-9 - norm;
3-5 - constant monitoring is required;
2.6-3 - high risk of hypoxia, emergency measures are required;
less than 2.6 - critical condition, the threat of death.

Pathological variants of CTG and their causes

The test result is considered suspicious if the absence of accelerations and decelerations is registered, the basal rate is up to 110 or above 160, the amplitude of variability is up to 10 and more than 25. The examination is repeated.

According to FIGO, CTG is considered pathological with the following data:

basal rate more than 180 or less than 100;
pronounced slow activity;
delayed decelerations for at least 30 minutes after uterine contraction;
monotonous rhythm, when the amplitude does not deviate by more than 5 beats in 1.5 minutes;
solitary slow activity after more than 3 minutes of acceleration;
weak activity of the child.

CTG will be bad with fetal hypoxia, heart disease, anemia, inflammation of the membranes. In such cases, an ultrasound is urgently performed to exclude entanglement with the umbilical cord. Possible violation of blood flow in the placenta. Some medications taken by the mother also cause heart rhythm disturbances.

Silent or monotonous

This is one of the possible pathological outcomes. What are the values in this case? The basal rhythm is in the normal range. Accelerations and decelerations are not fixed. The heartbeat graph looks like a straight line. Amplitude fluctuation with a monotonous schedule is no more than one beat per minute. Silent rhythm means heart defects incompatible with life, severe damage to the nervous system, severe oxygen starvation.

Sinusoidal and lambda rhythm

The first version of the curve is reflected in the graph with little variability. The rhythm deviates from 5 to 15 beats per minute. Deviations are repeated 2-5 times. Usually, such CTG results mean the presence of severe hypoxia, anemia, and may occur when the mother uses narcotic, psychotropic drugs.

With lambda rhythm, accelerations and decelerations often alternate. The cause of the pathological result is the pinching of the umbilical cord between the bones of the pelvis of the pregnant woman and the head of the baby. In this case, the child does not receive sufficient nutrients and oxygen. Its activity slows down, hypoxia develops.

Possible errors in deciphering the results

With all the advantages of cardiotocography, the device may show an erroneous result. It is necessary to evaluate the obtained value only in combination with other diagnostic methods. CTG 7 points and higher can be even with hypoxia, if the cells of the body have adapted to a lack of oxygen. A positive result also occurs with an actual lack of oxygen. In this state, there is enough air in the circulatory system, but the cells of the body do not perceive it.

Data indicating pathological abnormalities as a result of the examination can be obtained if the child pressed the umbilical cord during motor activity. This will show a poor result on the graph with the baby feeling normal. To obtain a complete picture and eliminate errors in decoding, the CTG method is used together with ultrasound and dopplerography.

It is impossible to determine the state of the fetus during fetal development by external signs. If we refer only to physical activity, then we can miss the alarming symptoms that are observed during intrauterine suffering. During the absence of technical devices, obstetricians focused on the heartbeat. In modern medicine, fetal cardiotocography is used.

What is a methodology?

Fetal CTG is literally explained as a recording of the heart rate simultaneously with the activity of the uterus. For registration, special fetal monitors are used. Their work is based on the Doppler principle. During the study, the intervals between the cycles of the child's cardiac activity are recorded. Tensometric sensors determine the force of uterine contraction. These indicators are recorded on a paper tape in the form of a curve. Combining the drawings of two lines in time allows you to analyze the condition of the fetus. The curve of uterine contractions also reflects its mobility.

There are two ways to conduct research:

Outer.
Interior.

The external method is used in the third trimester and during childbirth. In this case, the sensor is superimposed on the anterior abdominal wall. The woman is in a prone position. As long as the belly is not too big, she can lie on her back. By the time of delivery, in order to avoid pressure on the inferior vena cava, the pregnant woman is on her left side or in a half-sitting position.

There are two sensors on the abdomen. The first one shows the heartbeat. To improve transmission, a gel is applied to the location. The point of application is determined by the position and presentation of the fetus. For this, external obstetric techniques are used.

By the time of birth, most babies turn head down. Based on the results of probing small parts of the body, they decide in which direction the back is turned. On the other hand, they put the sensor. Usually this is the right or left side at the level of the navel. Indications are recorded separately for each child.

The second sensor records the activity of the uterus. It is applied to the right uterine angle. It is from it that a wave of contractions begins, which spreads to the entire organ.

The patient is given another sensor in her hands. With its help, she herself registers the moments of the movements of the child. When you click on the button, a corresponding mark appears in the ribbon.

How long the recording lasts depends on the individual characteristics. Usually this period is from 20 to 40 minutes. Deciphering the results of CTG requires at least 20 minutes of recorded basal rhythm, in which at least 2 episodes of movement of 15 seconds or more will be noted. The number of heartbeats should increase.

Fetal monitor Bionet FC 1400 for determining the fetal heart rate of the fetus

The duration of the recording depends on the periods of sleep and wakefulness of the child. In the mother's womb, he can sleep for up to 30 minutes.

Internal CTG is performed only in childbirth. This technique is not as popular as an external study. For its implementation, a spiral electrode is used, which is applied to the baby's head through the vagina. An intra-amniotic electrode is inserted to record uterine contractions. For diagnostics, certain conditions must be met:

outflowing amniotic fluid;
the cervix is 2 cm dilated.

This technique has not found wide application. In childbirth, it is more convenient to use the external recording method.

Types of studies of functional samples

A simple recording of CTG without the use of various stimuli is called a non-stress test. But in some situations, it is necessary to create conditions that resemble the birth process in order to find out how the physiology of the fetus will change during this period, whether the load during childbirth will be great for it. For this purpose, a stress test was developed.

Functional tests are used as stress, which become a model of childbirth. These are the following test types:

Oxytocin - a small amount of oxytocin is injected intravenously, which causes uterine contractions. CTG shows how the child's body will behave in these conditions.
Mammary according to the principle of action is similar to the first type. From irritation of the nipples, oxytocin is released.

Functional tests that affect the fetus are also used:

Acoustic test - the action of a sound stimulus can increase his heartbeat.
An atropine test is done by injecting atropine into a vein. A large number of complications and contraindications led to the fact that this technique is not used.
Palpation - through the abdominal wall, the midwife tries to displace the pelvic end or head of the fetus. It also leads to increased heart rate.

Currently, stress tests are rarely performed because they are associated with a high risk. With a well-recorded CTG, the doctor has enough data to understand the condition of the child.

When is research informative?

Medical protocols precisely determine at what stage of pregnancy a fetal CTG is done. They are based on the physiology of the child. Compulsory research is carried out from 32 weeks. In most cases, the doctor recommends performing CTG before each visit to the pregnant woman. But results can be obtained as early as 26 weeks. In some cases, according to indications, it is possible to carry out manipulations from 27 weeks.

So that the indicators of the state of the fetus can be interpreted, the optimal hours of the study are determined. This is the time of increased activity of the child: from 9.00 to 14.00, and from 19.00 to 24.00.

The following conditions distort the results of CTG:

hunger, in no case should manipulation be carried out on an empty stomach;
a plentiful meal, it is optimal to choose the time 1.5-2 hours after eating;
the introduction of glucose;
the use of sedatives, magnesia;
stressful situations;
condition after physical activity of the mother;
smoking and drinking alcohol.

For example, the result will be incorrectly interpreted if the mother climbed the stairs to the 2-3rd floor and immediately lay down under the CTG apparatus.

Diagnosis is difficult in overweight women. A thick fat layer on the anterior abdominal wall does not allow the sensor to recognize the baby's heartbeat.

Sometimes, if the sensor is applied incorrectly, the device shows a heartbeat of 65-80 beats per minute. Do not be afraid, this is recorded by the mother's own rhythm, and the sensor receives it from the pulsation of the aorta.

In childbirth, the use of CTG is mandatory. This allows you to control the condition of the fetus, to assess how contractions increase or they subside. Knowledge of uterine contractions is necessary for the correct adjustment of labor activity. Insufficient contractions are the need to stimulate labor so that they do not tire the woman even at the stage of cervical dilatation and do not turn into weakness in labor activity.

Preparation for CTG

The procedure is carried out in a antenatal clinic. Special preparation is not required. It is enough to follow simple rules:

Get enough sleep the night before your procedure. The condition of the mother affects the motor activity of the fetus.
Have a light snack before leaving the house. It is necessary to take into account the road to the clinic, so as not to be very full or, on the contrary, hungry.
Upon arrival, you need to rest a bit, sit down to restore your heart rate.
The procedure takes about 30 minutes, so a pregnant woman needs to worry about going to the toilet in advance.
Smoking mothers need to refrain from bad habits for 2 hours.

No other additional preparations are required.

Are there contraindications?

The technique is non-invasive and does not affect the condition of the fetus or uterus. The harm of CTG can only manifest itself when performing stressful functional tests. But at present, the level of technology and the qualifications of doctors make it possible to determine severe conditions without the use of special stimuli.

Basic concepts of CTG

Fetal cardiotocography

Indicators of the norm of the state of the fetus with CTG are evaluated according to the following data:

heart rate;
basal rhythm - the value of heart contractions, which is observed in the period between contractions for 10 minutes;
basal rate variability - the height of changes in heart rate;
acceleration - short acceleration of heart rate for 15 seconds or more or 15 heartbeats;
deceleration - decrease in heart rate by 15 beats or within 15 seconds.

Each of these concepts has its own norm. The basal rhythm should be in the range of 120-160 beats per minute. Fetal variability in CTG is 5-25 beats. If you look at the CTG tape, then the main fluctuation of the heart rate line should be within these limits.

Accelerations are sudden rises in the contractions of the heart. They must be present for 10 minutes, normally 2 or more heart rate rises are recorded.

Deceleration is a decrease in the number of heart contractions. Normally, they are absent or appear episodic, short and shallow. A prolonged decrease in heart rate indicates pathological conditions.

Deciphering the result

In order to quickly assess the result of CTG and identify initial fetal disorders, a system has been developed in which points are assigned for each indicator. The count is in the number of heartbeats.

Scoring helps determine the result of CTG:

8-10 speak of a normal state.
5-7 - initial signs of hypoxia. In such a situation, it is necessary to re-examine during the day. If the result remains the same, an additional examination is carried out. It includes an assessment of blood flow in the vessels of the placenta and uterus, ultrasound, determination of the biophysical profile.
4 points or less - a serious condition that requires emergency hospitalization. In this case, the decision is made either on intensive care or delivery.

The assessment of CTG is carried out not only taking into account the points. In many clinics, installed devices independently calculate such a value as an indicator of the condition of the fetus (PSP). Its rate should be less than 1.0. If PSP is equal to one or slightly exceeds, then repeated cardiotocography is recommended.

PSP 1.05-2.0 indicates the initial signs of deterioration. A woman is prescribed treatment, and after 5-7 days, control of cardiotocography. An increase in PSP to 2.01-3.0 is an indication for hospitalization and serious treatment. Exceeding this indicator of 3.01 - an emergency delivery is necessary.

The requirements for the norm for the result of the study differ depending on the gestational age. By the time of full-term pregnancy (from 38 weeks), all indicators should be within the specified norm. In an immature child at week 36, slight deviations are allowed, but the number of points should not be less than 8, there are sufficient numbers of both acceleration and deceleration in the recording tape. Low variability within 3-6 is allowed.

If there are no pronounced accelerations and decelerations in the cardiotocography record, this cannot be called the norm. There is a monotonous fetal heartbeat, which indicates hypoxia. In some cases, such a change in rhythm is observed during the child's sleep. To verify this, the midwife or doctor will try to move the fetal head through the abdomen.

The ability of the nervous system to respond to stimuli is indicated by the fetal reactivity index. But this indicator is not used in isolation. To decipher it, doppler data of the placenta and uterine vessels are used. With a decrease in blood flow, development can be judged.

The information received from the fetal sensor during childbirth is very helpful in correcting their course. There are situations when the fetus pinches the umbilical cord during a fight. On the screen, this is noted as a pronounced decrease in heart rate and its long recovery. In such a situation, the doctor decides not to administer oxytocin in order to increase uterine contractions. Sometimes you even need to move the head through the vagina a little to ensure normal blood flow.

In severe cases, the gynecologist may notice in time a sharp decrease in the rhythm after the next contraction, which is not restored during the rest period. If there is evidence that a woman had infectious diseases during pregnancy, when the amniotic fluid was opened, they were meconial in nature, then an emergency decision may be made in the interests of the child.

Is CTG harmful to the fetus?

Non-stress tests do not pose any danger to either the baby or the course of pregnancy. This is a good help for the doctor, which helps to respond correctly when the situation changes. You should not decipher it yourself: a non-specialist is not able to take into account all the available factors and draw the right conclusions.

Can the procedure be done at home?

Theoretically and practically, this is possible, but the cost of devices for cardiotocography is high (several hundred thousand rubles), and small amateur devices that only record the heart rate and do not record or analyze other parameters have no special diagnostic value.

Sometimes, when the situation requires daily monitoring, a woman is temporarily provided with a device for home use, this decision is made by the attending physician. Most often this happens with patients of modern perinatal centers, which are better equipped than consultations.

Home measurements will be able to show the condition of the baby, as well as understand that there will be childbirth soon, if the baby is moving strongly or, conversely, has calmed down, and characteristic “waves” appear on the graph, indicating the onset of contractions and preparation for childbirth. This can happen at any time, starting from 37-38 weeks. Women whose onset of labor should not coincide with their stay at home are advised to go to the maternity hospital in advance. In a hospital setting, if necessary, a daily CTG will be performed, and the expectant mother will not have to worry about the condition of her baby.

For information on how CTG is carried out, as well as other useful information on pregnant women, see below.