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If points are not indicated in KTG. CTG (cardiotocography): indicators, results and interpretation, norms

What is CTG in pregnant women? Cardiotocography (CTG) is a method of functional study of the state of the fetus in the womb of a pregnant woman, which is based on a consistent recording of the child's heart rate and its changes in accordance with contractile movements of the uterus, exposure to environmental factors and the activity of the baby himself.

This recording of the heartbeat is carried out for 15 minutes and can be carried out both in a calm state of a woman outside the birth process, and during contractions and childbirth. This feature makes CTG a fairly effective and useful method for resolving the issue of the tactics of childbirth.

What does CTG show? First of all, this type of research is carried out in order to obtain information about fetal heart rate, the regularity of his cardiac activity, as well as active movements.

In addition, the information content of CTG is very important in relation to determining the frequency of contractions of smooth muscle cells of the uterus and the child's response to these contractions.

Cardiotocography is effective method research for exclusion or timely determination of pathological conditions of mother and child that threaten the course of pregnancy and the future health of the newborn baby, such as intrauterine infection of the fetus, oligohydramnios, congenital abnormal development of the cardiovascular system, placental insufficiency and the threat of childbirth that begins earlier than planned.

The main indications for CTG

A woman with Rh-negative blood, at risk of developing hemolytic disease of the newborn.
A history of preterm labor, miscarriages, and abortions.
Sensations of reduced fetal movements in the pregnant woman herself.
Complications during pregnancy (multiple fetuses, polyhydramnios, oligohydramnios, fever or subfebrile temperature in a pregnant woman, incorrect presentation of the baby, post-term pregnancy).
Disorders in the child that were previously found in (developmental delay, violations in amniotic fluid, decrease in activity, pathological changes in blood circulation in the placenta, too large or small size of the child that does not correspond to the month of pregnancy).
Endocrine and systemic diseases in a pregnant woman (the first and second types, diseases of the cardiovascular system,).

This method of studying the state of the child during his intrauterine life is safe, since the sensor reproduces an ultrasonic wave of weak strength, not causing a negative effect on the baby.

At what time do fetal CTG

The use of cardiotocography can be started approximately from, but a high-quality and informative recording of the above parameters characterizing the state of the child in the womb is possible only from.

This is due to the development in the baby of periodically replacing each other cycles, when he is active or calm in motor terms. The most active baby in the period from 9 to 14 pm, as well as from 19 to 24 pm.

How to prepare for CTG during pregnancy? CTG is contraindicated after a meal, since an increased one can significantly affect the fetus, increasing its movement and reaction to external environmental stimuli.

How is fetal CTG done during pregnancy

Cardiotocography is performed using specialized sensor, which has an ultrasonic effect and is based on the effect of .

This device is tightly fixed on the stomach of a pregnant woman in front where the baby's heart sounds are most clearly heard. This area is pre-determined without problems with an obstetric stethoscope.

The sensor, producing a signal in the form of an ultrasonic wave, directs it towards the baby's heart in the womb. The wave is reflected from the heart, which is perceived again by the same sensor as a result. The received information is converted into values fetal heart rate per minute. The results of the study are reproduced by sound, light and graphics on the tape.

If the pregnancy is normal, CTG is carried out no more than once a week. In case of a complicated course of pregnancy, but with good results of previous methods for examining the fetus, this procedure is performed with a pause of an average of 6 days.

If it has developed child hypoxia in the womb, CTG is indicated for daily or one day later for constant dynamic monitoring of the child's condition and timely action for emergency childbirth.

Deciphering the results of fetal CTG during pregnancy

Evaluation of the results of the performed analysis of cardiotocography is carried out specialist in a number of indicators, which include the basal rhythm, variability, acceleration, deceleration and, finally, the activity of the baby's movements in the womb. All this is depicted at the end of the manipulation on paper in the form of graphs of various shapes.

How to decrypt CTG? You should not try to decipher your CTG yourself, since you, not being a doctor, will make a mistake when deciphering the fetal cardiotocography in scoring the results obtained, which, of course, can harm the child.

Basal Rhythm is the average value of the fetal heart rate. Normally, the basal rhythm reaches from 110 to 160 heart beats per minute with the calmness of the baby and the pregnant woman. When the child moves, the frequency of contractions increases to values ranging from 140 to 190 beats.

All normal basal rate values indicate no hypoxia baby's body. And the increase, as well as the decrease, are a clear sign of fetal hypoxia, which, first of all, is detrimental to it. nervous system, though not yet fully developed.

Variability(in other words, amplitude) - a change in the value of the heart rate and its amplitude relative to the obtained values of the baby's basal heart rate.
Outside of pathology, the heart rate of a child in the womb should not be constantly the same and monotonous, which is well visualized by a continuous change in numerical values on the monitor during CTG. Normal changes in the relevant parameters should be between 5 and 25 beats per minute.

An increase in amplitude may indicate the same fetal hypoxia or, which, of course, is a pathology. Reduced amplitude values may be normal if the baby is in a calm state at the time of the CTG. In order to “wake up” the baby, mom can simply eat some sweet.

Acceleration(acceleration) - an increase in the number of heart beats in comparison with the level of the basal heart rate. The magnitude of the acceleration is expressed on the cardiotocogram in the form of teeth, normally it is at least 2-3 times within 15 minutes. It is permissible to increase the number of accelerations up to 4 pieces in half an hour. Their complete absence for the specified time period is pathological.

Deceleration(decreased) - a decrease in the values of heart beats in comparison with the level of the basal heart rate. The value of deceleration is already expressed in the form of dips (“negative” teeth). Normally, such manifestations on the graph should not be present or be insignificant in depth, duration and occurrence.

The deterioration of the condition of the baby in the womb can be confirmed by the occurrence of decelerations after 20 minutes of the study. Also a bad result is their repetition and different appearance throughout the entire graph. All this may indicate decompensated fetal stress.

In general, decryption norms of CTG results fetus looks like this:

Basal rhythm - 120-159 per minute in a calm state.
Variability from 10 to 25 beats per minute.
2 or more accelerations within 10 minutes.
No decelerations.

Pathological CTG as follows:

Basal rate - less than 90 and more than 180 per minute.
Variability less than 5 beats per minute.
No or few accelerations.
Availability different kind decelerations.

Fisher ten-point scale

The results of cardiotocography are evaluated by specialists on a ten-point Fisher scale, which is based on assigning points in the amount from 0 to 2 to each of the above indicators. These scores are summed up, and a general conclusion is made about the information content of CTG and the presence of pathological changes in the fetus. The so-called "indicator of fetal health"(PSP).

If score KTG was 1 to 5, then the condition of the baby in the womb is poor, he experiences hypoxia (lack of air).
What does it mean if the sum of the CTG scores was 6-7 ? The child shows initial signs of developing oxygen starvation.
What does it mean if the sum of CTG scores from 8 to 10? This indicates the norm and good condition of the baby.

With a PSP of 1-5 points, immediate delivery is indicated, with a PSP of 6-7 points - repeated CTG, with a PSP of 8-10 points - continued periodic monitoring of the pregnant woman and the fetus using this research method.

How can gestational age affect CTG performance

If CTG is performed earlier than 29-32 weeks of pregnancy, it can become uninformative and meaningless, since it is by this period that the fetus forms a sleep and wakefulness regimen, and earlier it manifests itself only calmness in the mother's stomach.

Depending on the week, the indicators are approximately the same, but the smaller the week, the higher the variability (amplitude).

The fact that the doctor did not like the results of cardiotocography does not mean the final determination of the fetus of hypoxia and pathology in principle. There are cases when young doctors without sufficient work experience misinterpreted the information that the received graph carries, although everything was completely normal for the baby and his mother.

Therefore, do not rush and immediately panic when you get a bad result. But one should not relax either, since this may actually indicate a real pathology that requires immediate treatment and action by medical workers.

Most likely, if the results are alarmingly abnormal, the doctor will ask you to go to hospital in maternity hospital, where they will conduct regular CTG and will be able to quickly respond in a dangerous situation.

How contractions appear on CTG

This study is required indicate the presence of contractions, since normally the uterus should respond to the active motor activity of the baby with its spasms. In addition, the uterus has the ability to spontaneous contraction. On CTG, in response to contractions, a decrease in the number of heartbeats of the child and deceleration will be seen, which is rare.

The second curve (hysterogram) reflects the increase in the force of contraction of the myometrium (the muscular layer of the uterus) during contractions. The higher it is, the stronger the contractions. Some women in labor do not feel contractions, CTG helps determine their strength and frequency.

What is the fetal reactivity index

This indicator tells the specialist about the state of the fetus's reactivity of its nervous system to external influences, which, first of all, affects the state of the cardiovascular system.

The calculation is made in a point system and further interpreted:

0 points mean the absolute absence of reactivity in the baby.
1 point means severe disturbances in the reactivity of the organism.
2 points mean pronounced violations of the baby's reactivity.
3 points mean a moderate degree of disturbances in reactivity.
4 points mean the initial stage of the child's reactivity pathology.
5 points mean normal reactivity in the fetus.

What is a non-stress test?

This type of study of the state of the baby in the womb is heart test according to the movements of the child.

A good result is a negative non-stress test (the presence of 2-3 increases in the number of heartbeats by about 15 beats per minute for 15-20 seconds). In the case of a positive or no result at all, it can be concluded that the baby is hypoxic, which, in fact, can be a false phenomenon if at the time of the study the fetus was calm and asleep. In this case, the non-stress test is shown to be repeated.

Cardiotocography is one of the most accurate methods for determining the hypoxia of a baby in the womb of a pregnant woman, which is very valuable for its timely diagnosis and taking measures to eliminate it. In the presence of hypoxia on CTG, there are the following changes:

Reduction or complete deficiency of fetal heart beats.
An increase in heart rate when the fetus moves or the uterus contracts involuntarily.

Erroneous evaluation of CTG results

Errors in the interpretation of information obtained using cardiotocography, of course, are possible. For example, in case of hypoxia, but despite the fact that the baby's tissues have already managed to adapt to it, CTG is not able to show this pathological condition. The same can happen if there is a sufficient amount of oxygen in the bloodstream, but the tissues cannot adequately accept and use it, which indicates actual fetal hypoxia.

The presence of errors obliges specialists to evaluate the results of CTG only in combination with the results of other studies carried out by a pregnant woman, and after that make a final diagnosis.

Fetal cardiotocography (CTG) video

We invite you to watch a video about fetal CTG. The obstetrician-gynecologist will tell you how and why this examination is carried out, how its results are evaluated, what are the normal CTG indicators.

Any pregnant woman will sooner or later undergo a CTG procedure, some of the readers have already met with this study. That's why tell us about your impressions from cardiotocography, how its results were interpreted to you, and what gave you the passage of this painless manipulation. Do not forget to leave feedback, ask questions about CTG, the answers to which you are most concerned about or still remain unclear.

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.

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. 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. Acceleration means an increased amount of heartbeat, compared to the level of basal rhythm 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.

Pregnancy is not a disease, however, it is a special period during which the condition of a woman and a small resident in her womb is monitored most closely. And it's great!

Timely analyzes, examinations and procedures allow you to track the course of pregnancy and respond in a timely manner to negative deviations in it. They also allow doctors to prepare for childbirth, if there is a possibility of a complicated course.

Therefore, the expectant mother should not be annoyed if the doctor sends her to another procedure called "cardiotocography".

Cardiotocography (CTG) is a diagnostic method for assessing the condition of the fetus during pregnancy and childbirth through the frequency of its heartbeats and its fluctuations at rest, activity, with uterine muscle contractions, and exposure to external stimuli.

According to the results of cardiotocography, together with ultrasound and, the doctor will be able to detect the onset of fetal hypoxia (oxygen starvation), possibly arrhythmia, in time and identify the causes of this condition.

CTG is prescribed, according to the Order of the Ministry of Health and Social Development of the Russian Federation, starting from the 28th week of pregnancy.

In fact, doctors rarely prescribe this examination before the 32nd week, believing that until this time CTG is uninformative. In total, during the third trimester, during the normal course of pregnancy, a woman will have to undergo two CTGs.

If necessary, the doctor can prescribe the CTG procedure as often as he sees fit, even daily.

Indications for additional monitoring of fetal heart rate through CTG analysis are:

unfavorable result of the previous CTG;
suspicion of pathology of fetal development;
or ;
a decrease in the baby's motor activity noted by a woman;
delayed pregnancy;
the presence of diseases in a pregnant woman such as: diabetes, autoimmune diseases, infectious diseases, etc.;
blood future mother and fetus;
noted on ultrasound;
pathological course of previous pregnancies and delivery;
entanglement of the fetus with the umbilical cord detected during ultrasound.

This method of examination does not pose any danger either to a pregnant woman or to a future newborn baby.

But the information obtained with the help of CTG allows you to identify and reduce the risk of intrauterine suffering of the baby.

How to prepare for the CTG procedure and how to do it?

The CTG procedure is carried out using a special apparatus, consisting of an ultrasonic sensor and a strain gauge, which are attached to the woman's abdomen and an electronic heart monitor system.

The latter receives data on fetal heartbeats and uterine contractions of a pregnant woman, processes them and displays the result on a tape in the form of graphs. How to prepare for CTG during pregnancy?

Cardiotocography does not require additional preparation. The only thing you can eat before the procedure is something sweet so that the baby moves more actively.

CTG is a completely painless procedure, during which the expectant mother only needs to get comfortable in a chair or on a couch and not make sudden movements so that the sensors do not slip off the tummy.

Requirements for the patient: to remain calm during the operation of the cardiotocograph, i.e. approximately for 30-60 minutes. Everything else will be done by the health worker and the equipment.

First, the midwife or doctor performing the procedure, using a conventional ear stethoscope, determines the area on the woman's abdomen where the fetal heartbeat is most clearly audible.

On this place, treated with a conductive gel, a sensor-electrode is installed and fixed with a wide tape-belt, which captures and amplifies signals about the movement of the fetal heart valves.

Based on the signals about cardiac impulses, a graph is drawn that displays changes in heart rate throughout the entire procedure.

In parallel, on the abdominal wall of a woman, just below the navel, in the region of the bottom of the uterus, a pressure sensor (strain gauge) is fixed, which transmits data on the tone of the myometrium (uterine muscles).

The position of the woman during the CTG of the fetus: usually reclining, sitting or lying on her side in a horizontal position, as desired.

Sometimes a situation arises when during the procedure the baby is fast asleep and the woman cannot fix the movements. In such a situation, health workers recommend waking up the baby by touching the stomach and stroking. This is absolutely not worth doing.

Additional vibrations are reflected in the recording of the curve, and the apparatus gives false results.

If not a single movement is recorded in this way, you will have to undergo the procedure on another day. But this rarely happens, because the intrauterine sleep of the baby is very short and tremors will still be recorded at the beginning of the procedure or at the end.

The definition of CTG, for which this type of diagnosis is carried out - you will learn about this from the video.

Varieties of devices for CTG

Cardiotocography began to gain popularity only in the last twenty years, when data on the condition of the fetus obtained by CTG began to be confirmed by data on the condition of the same babies after childbirth.

This happened due to the improvement of the equipment developed for the survey.

Currently, almost every antenatal clinic and pregnancy clinic, as well as maternity hospitals, are equipped with cardiotocographs.

The most unpretentious CTG devices or fetal (fetal) monitors only provide data on the fetal heart rate, its motor activity and uterine contractions to the tape. In the future, the doctor interprets the graphical indicators and draws conclusions about the satisfactory condition of the baby. Such devices, so to speak, of the first level, are practically not used anymore.

Modern devices for CTG examinations, which are most widely in demand by medical institutions, are expert-level devices.

They differ, firstly, in high power, and secondly, in the most sensitive sensors and the most accurate display of data.

In addition, the instruments are configured in such a way that the data processing of the output graphs occurs automatically. It remains for the doctor to prescribe additional examinations or draw up the necessary treatment tactics, if necessary.

Some CTG devices are equipped with additional options that allow you to assess not only the condition of the fetus, but also the general condition of the pregnant woman: blood pressure, ECG, etc.

Recently, there have been opportunities for monitoring fetal heart rate remotely. A sensor that captures signals about the fetal heartbeat sends data online to the portal via a smartphone connected to the Internet, where they are analyzed and sent to the doctor as a result.

Values of indicators and norms: decoding the results of the analysis

The purpose of the CTG procedure during pregnancy is to obtain quantitative and qualitative values for some indicators.

The norms of CTG during pregnancy are as follows:

Basal fetal heart rate.

Represents the baby's average heart rate. A normal rate is from 110 to 160 beats / min.

With deviations from the normal basal rhythm, bradycardia is diagnosed if the heart rate is below 110 bpm. or tachycardia if the heart rate is above 160 bpm.

With deviations not exceeding 20 bpm, they speak of a mild form of heart rate disturbances.

More serious deviations indicate the possible presence of intrauterine infection, cord entanglement.

The cause of abnormal indicators may be the effect of narcotic substances on the mother's body, fever, hormonal disorders in the expectant mother.

Heart rate variability.

Shows the number of deviations of the fetal heart rate from the basal rate in 1 minute. The presence of a variability of more than 6 per minute is considered a good indicator.

In practice, the amplitude of deviations in the number of heartbeats from the basal level per minute is more often assessed. Well, if it is 6-25 strokes.

Low variability (less than 5 per minute), in which the graph resembles a straight line, is characterized as a monotonous fetal heart rate and, in combination with bradycardia, almost certainly indicates fetal suffering from hypoxia, or a violation in the cardiovascular system.

Preservation of the normal basal level of the fetal heart rate, along with the monotonous rhythm of the heart, may also mean that the fetus is at rest, sleeping.

Increased values of variability can also be caused by fetal hypoxia, as well as the influence of external stimuli on its nervous system, and the mother taking any drugs that increase heart rate.

The variability of the basal rhythm of the fetal heart rate on the graph in some cases is reflected as a sinusoidal curve. Such a picture emerges when the amplitude of deviations in the rhythm of the child's heart rate is 5-15 beats per minute, if the regularity of such deviations is 2-5 per minute.

The described phenomenon is called "sinusoidal rhythm" and in most cases is associated with severe fetal hypoxia, intrauterine anemia, etc.

Accelerations

The increase in the work of the fetal heart compared with the basal rhythm.

If within 10 minutes at least two increases were determined, more than 15 beats per minute, lasting more than 15 seconds, then this indicator is counted as excellent.

Monotonous accelerations, especially in combination with severe tachycardia, give reason to suspect fetal hypoxia.

Decelerations.

This is a decrease in the fetal heart rate compared to the basal rhythm.

An alarm should be caused by the occurrence of reductions of more than 15 beats / min. for more than 15 seconds.

This does not always indicate pathology and requires consideration of such an event in conjunction with the assessment in this episode as well as previous fetal activity.

The detection of obvious decelerations on the CTG graph indicates severe fetal hypoxia, a violation of the conduction of the placenta, its functions.

The number of fetal movements.

During the CTG, the indicator of fetal movements is necessarily removed. The moment of movements is noted either by the future woman in labor, squeezing a special device with her hand, or they are automatically recorded by the monitor's sensors.

An unfavorable sign is considered if, when fixing an increase in heart rate, no movements of the baby in the womb are noted. Or, during movements, no response was found in the form of accelerations.

If under such conditions there is no deterioration in the work of the heart, then the result of CTG is interpreted as favorable.

Otherwise, further action must be taken.

The decoding of CTG is such that each of the indicators is evaluated by the doctor on a point scale.

Most often, the Fisher scale is used to assess CTG. Depending on how close to the ideal indicators this or that parameter recorded by the CTG sensor is assigned 0-2 points

The total value of all points demonstrates an assessment of the child's condition:

a score of 8 to 10 is considered normal;
scored 5-7 points are the reason for repeated CTG and may indicate a slight oxygen starvation of the fetus or an unfavorable state of the placenta.

As a rule, CTG for 5-7 points may indicate a beginning;

less than 5 points, obtained according to the results of CTG, mean the danger of intrauterine death of the fetus due to hypoxia;

After the first 10 minutes after the start of the examination, a decision can be made to terminate the CTG procedure, with a statement of the satisfactory condition of the fetus.

This conclusion is made in full compliance with the so-called Dows-Redman criteria by the 10th minute of CTG, namely:

lack of decelerations;
compliance with the basal rhythm within normal limits (120-160 beats / min);
the amplitude of heart rate deviations from the basal value is not less than 6 and not more than 25 beats / min;
fixation of at least one fetal movement or at least three accelerations;
marked sporadic palpitations;
short-term variability of at least 3 ms.

If after 10 minutes of CTG not all the Dawes-Redman criteria are found, then the examination continues until this happens, but not longer than 60 minutes. If this did not happen, then a note is made that the Dawes-Redman criteria are not met and additional examinations are assigned.

Many pregnant women, even before going to the doctor, try to decipher the results of CTG on their own. Of course, you can understand the hardware data, but it’s better to entrust the interpretation of the results to an experienced doctor, since the results of the procedure may vary depending on what time of day the pregnant woman underwent the procedure, what drugs she takes, what position the woman was in, etc. d.

For example, quite often the Dawes-Redman criteria remain unfulfilled by a certain time. But this does not mean at all that CTG is bad.

When deciphering the CTG, an experienced specialist looks not at the number of points, but at the values of each of the indicators.

Whatever the results of CTG, it is worth remembering that their reliability remains only for a few hours. And the next day the situation can change.

If the result of the examination is unsatisfactory, you should not panic, but prepare for a repeated cardiotocogram, as well as for undergoing other diagnostic procedures (, Doppler, etc.).

Even the most modern heart monitor does not give a ready-made diagnosis. The final verdict on the condition of the fetus is made by the attending physician, based on the totality of data from all diagnostic methods.

During the bearing of a child, the expectant mother will learn many new letter abbreviations for herself - ultrasound, BPR, DBC, hCG. They become understandable and even familiar. In the last trimester, another “classified” diagnostic test in the letter code is assigned - CTG. Its implementation usually does not raise questions, but only a few can decipher the results. How to understand what is written in the conclusion of the CTG, we will tell in this material.

What it is?

Cardiotocography (this is how the name of the examination stands for) is a non-invasive, safe and painless way to find out what condition the baby is in, how he feels. Such an examination is carried out starting from 28-29 weeks of pregnancy. Most often, expectant mothers receive a referral for CTG at 32-34 weeks for the first time, and then the study is repeated immediately before the onset of the birth process.

During the birth itself, CTG is often used to determine if the baby has experienced acute hypoxia in the process of passing through the birth canal.

If the pregnancy is going well, there is no need for additional CTG. If the doctor has fears that it proceeds with complications, then CTG is assigned individually, some have to go through it weekly or even once every few days. There is no harm from such a diagnosis either for the child or for the mother.

Cardiotocography allows you to find out features of the baby's heartbeat. The child's heart reacts immediately to any unfavorable circumstance, changing the frequency of its beating. In addition, the method determines the contraction of the uterine muscles. Registration of changes occurs in real time, all parameters are recorded simultaneously, synchronously and displayed in graphs.

The first graph is a tachogram showing changes in the baby's heartbeat. The second is a graphic representation of uterine contractions and fetal movements. It is called a hysterogram or tokogram (women often use the abbreviation "toko"). The heart rate of the baby is determined by a highly sensitive ultrasonic sensor, and the tension of the uterus and movements are captured by a strain gauge.

The data obtained are analyzed by a special program that displays certain numerical values on the research form, which we will have to decipher together.

Technique

The expectant mother should come to CTG in a calm mood, because any worries and experiences of a woman can affect her baby's heartbeat. It is advisable to pre-eat, go to the toilet, because the examination lasts quite a long time - from half an hour to an hour, and sometimes more.

You should turn off your cell phone, sit comfortably in a position that will allow you to spend the next half hour comfortably. You can sit down, lie down on the couch, take a semi-recumbent position of the body, in some cases, CTG can be performed even while standing, the main thing is that the expectant mother should be comfortable.

On the stomach in the area of attachment chest the child is fixed with an ultrasonic sensor that will record the slightest changes in the nature of the heartbeat and heart rate.

A wide belt is put on top of it - a tensiometric sensor, which will determine by slight fluctuations in the volume of the belly of the expectant mother when the uterine contraction or movement of the baby has occurred. After that, the program turns on and the study begins.

At this stage, a pregnant woman may have two questions - what do the percentages on the fetal monitor mean and what do the sounds that come during CTG mean. Let's help you figure it out:

Sounds during exploration. The sound of the baby's heartbeat, already familiar to the expectant mother, does not need to be explained. Previously, ultrasound specialists have probably already let the woman listen to the knocking of a small heart. During CTG, a woman, if the device is equipped with a speaker, will hear it all the time. Unexpectedly, a woman may hear a long, loud noise, similar to interference. This is how the baby moves. If the device suddenly starts beeping, this indicates a loss of the signal (the baby turned and moved far away from the ultrasonic sensor, the signal was interrupted).
Percentage on the screen. Percentage indicates the contractile activity of the uterus. The more actively the main reproductive female organ contracts, the more reasons the doctor has for hospitalizing a woman. If the values approach 80-100%, we are talking about the beginning of contractions before childbirth. Indicators in the range of 20-50% should not frighten a woman - she will definitely give birth early.

Deciphering the results

Understanding the abundance of numbers and complex terms is not as difficult as it seems at first glance at the CTG result. The main thing is to understand and have a good idea of what concepts are being discussed.

Basal heart rate

Baseline, or basal heart rate - the average value of the baby's heart rate. A mother who comes to CTG for the first time may be surprised that the baby’s heart beats very unevenly, the indicators change every second - 135, 146, 152, 130 and so on. All these changes do not escape the program, and for the first ten minutes of the examination, it displays the average value, which for this baby will be the base or basal.

This parameter in the third trimester does not change depending on the specific week, as some pregnant women think. And at 35-36 weeks, and at -40, the basal heart rate only reflects the average values of the baby's heart rate and in no way indicates either the gestational age or the sex of the child.

The norm of basal heart rate is 110-160 beats per minute.

Variability

As can be understood from the sound of the word, this concept hides variants of something. In this case, options for deviation of the heart rate from the baseline values are considered. In medicine, another name for this phenomenon is used, which can also be found in conclusion - oscillations. They are slow and fast.

Fast ones reflect the slightest changes in real time, because, as already mentioned, each beat of the fetal heart displays a different heart rate. Slow oscillations are low, medium and high. If in a minute of real time the frequency of contractions of the child's heart was less than 3 beats per minute, they speak of low variability and low oscillation. If the range per minute was from three to six beats, then we are talking about medium variability, and if the fluctuations in one direction or another amounted to more than six beats, the variability is considered high.

To imagine this more clearly, let's give an example: in a minute, the device registered a change in the fetal heart rate from 150 to 148. The difference is less than 3 beats per minute, which means that this is a low variability. And if in a minute the heart rate changed from 150 to 159, then the difference is 9 beats - this is a high variability. The norm for a healthy baby with an uncomplicated pregnancy is fast and high oscillations.

Slow oscillations are of several types:

monotonous (changes in heart rate by five or less beats per minute);
transient (heart rate per minute changes by 6-10 beats per minute);
undulating (heart rate changes by 11-25 beats per minute);
jumping (more than 25 beats per minute).

If in a minute the heart rate jump looks like this: 140-142 beats / min, then we are talking about a monotonous slow oscillation, if in a minute the heart rate has changed from 130 to 160, then we are talking about a jumping slow oscillation. Wave-like oscillations are considered normal for a healthy baby, and other types almost always accompany various pathologies of pregnancy - umbilical cord entanglement, hypoxia, Rhesus conflict.

Accelerations and decelerations

Quantitative change is oscillations, and qualitative change is acceleration and deceleration. Rhythm increase - acceleration. On the graph, this looks like a peak, a clove. Deceleration of the rhythm - deceleration, is graphically depicted as a peak with the top down, that is, a failure. Acceleration is an increase in the baby's heart rate by 15 beats per minute or more and maintaining this rhythm for more than 15 seconds.

Deceleration is a decrease in the heart rate value from the base value by 15 beats down and maintaining such a rhythm for 15 or more seconds.

There is nothing wrong with the accelerations themselves if more than two of them are registered in 10 minutes. However, too frequent accelerations, the same in duration and occurring at regular intervals, are an alarm, the child is uncomfortable. In principle, decelerations (decreasing) are not characteristic of a healthy baby, but a small number of them with other normal indicators of cardiotocography may be a variant of the norm.

perturbations

How many movements should be, the question is quite complicated, because there is no unambiguous answer to it. All children have different physical activity, they are affected not only by their own well-being, but also by factors that do not depend on it - the mother's diet, her mood and emotional state, and even the weather outside the window.

If the baby wants to sleep at the exact moment when you need to do CTG, his movements will be minimized.

Considered a good sign if at least a few movements are registered in the child during CTG: in half an hour - at least three, in an hour - at least six. Too frequent sudden movements are an alarming sign that may indicate violations in the state of the crumbs. Too little movement is also not a good indicator. However, if all other CTG values are normal, then the doctor will assume that the child simply overslept all this hour, and will ask the woman to come for an examination again in a few days.

It is not so much the movements themselves that are considered important, but the relationship between them and the number of accelerations. Normal healthy child when moving, the heart rate increases. If this connection is broken and movements do not accompany heart rate rises, and the accelerations themselves occur spontaneously and are not associated with movement, the well-being of the baby is called into question. On the graph, the movements look like dashes in the lower part, where uterine contractions are noted.

Uterine contractions

The contractions of the uterine muscles are depicted in the lower graph. Visually, they look like wavy drops, because the contraction starts smoothly and ends no less smoothly. Do not confuse them with movements, they are marked with short vertical dashes. It is interesting that the strain gauge belt detects even those contractions that a woman does not physically feel.

Percentages mean contractile activity.

It is definitely impossible to determine the tone of the uterus on CTG, because the pressure inside the uterus can really be measured in only one way - to insert a thin long sensor-electrode into its cavity, but this is impossible until the fetal bladder is safe and sound, and childbirth has not begun. Therefore, the value of the tone of the uterus is constant - 8-10 millimeters of mercury are taken as the base rate. A program that analyzes all indicators, according to the contractility of the main female reproductive organ, can "conclude" that this pressure is exceeded. Only then can the doctor suspect tone, but manual examination on the gynecological chair and ultrasound will be needed to confirm.

sinusoidal rhythm

If the conclusion says "sinusoidal rhythm - 0 min", then this is a very good indicator. Such a rhythm, indicated on the graph as sinusoids repeating at regular intervals, the same in duration, indicates severe pathologies. The number of accelerations and decelerations is minimal or absent at all. If such a graphic picture persists for about 20 minutes, doctors may suspect a big problem.

Such a rhythm occurs in children with severe uncompensated hypoxia, severe intrauterine infection, and a strong Rh conflict. Seven out of ten babies who showed a sinusoidal rhythm on CTG for 20 minutes or more die in utero or immediately after birth.

Table of norms of the main indicators:

Assessment of the state of the fetus - points

To assess the condition of the fetus, doctors use methods for calculating the results in points. Reasonable questions are often raised in women, which means 4 or 5-6 points on CTG, which can be indicated by 10, 11 or 12 points. The interpretation depends on which scoring method the program operated on or how the doctor calculated the result if the assessment was made “manually”.

The most commonly used scoring system is Fisher.

This is a twelve-point system in which a certain number of points is awarded for each indicator.

By Fischer

Fischer scoring table (Krebs modification):

The indicator determined on CTG	1 point is awarded if:	2 points are awarded if:	3 points are awarded if:
Base heart rate	Less than 100 bpm or more than 100 bpm	100-120 bpm or 160-180 bpm	121-159 bpm
Expression of slow oscillations	Less than 3 bpm	3 to 5 bpm	From 6 to 25 bpm
Number of slow oscillations	Less than 3 during the study period	3 to 6 per study period	More than 6 during the study period
Number of accelerations	Not fixed	1 to 4 in half an hour	More than 5 in half an hour
Decelerations	late or variable	Variable or late	Early or not fixed
perturbations	Not fixed at all	1-2 in half an hour	More than 3 in half an hour

The interpretation of the results looks like this:

,10, 11, 12 points- the child is healthy and feels quite comfortable, his condition does not cause concern;

6, ,8 points- nothing threatens the life of the baby, but his condition is of concern, since such an indicator may be a sign of initial pathological changes and adverse external influences. A woman should do CTG more often to monitor the baby in dynamics;

5 points or less- the child's condition is threatening, there is a high risk of intrauterine death, stillbirth, neonatal death in early postpartum period. The woman is sent to the hospital, where an urgent diagnosis is carried out, and in most cases everything ends with an emergency caesarean section to save the baby's life.

According to FIGO

This evaluation table was adopted by the specialists of the International Association of Gynecologists and Obstetricians. It is less commonly used in Russia than the Fisher score, but is more understandable for expectant mothers.

FIGO interpretation table:

PSP

It stands for "an indicator of the condition of the fetus."

It is very difficult to visualize by what algorithms and mathematical formulas this calculation takes place if a mathematics diploma is not on the shelf at home. This is not required. It is enough for the expectant mother to know what PSP indicators are considered the norm and what they mean:

PSP less than 1.0. This result means that the baby is healthy, he is comfortable, his well-being and condition are not disturbed. This is a good result, in which the doctor lets a pregnant woman with CTG go home with a clear conscience, because nothing bad should happen to the baby.

PSP from 1.1 to 2.0. Such a result indicates the likely initial changes that are different from the normal state of health. Violations with such a PSP are not deadly, but they cannot be ignored either. Therefore, a woman is asked to come to CTG more often, on average - once a week.

PSP from 2.1 to 3.0. Such indicators of the condition of the fetus are considered very alarming. They may indicate severe discomfort experienced by the child in the womb. The reason for the baby's troubles can be a Rh conflict, a state of oxygen deficiency, entanglement with the umbilical cord, intrauterine infection. The pregnant woman is sent to the hospital. She is shown a more thorough examination and, possibly, an early delivery by caesarean section.

PSP above 3.0. Such results may indicate that the child's condition is critical, he is threatened with intrauterine death, which can occur at any time. The woman is hospitalized urgently, an emergency caesarean section is shown to save the baby.

Stress and non-stress tests

Conventional CTG, which is performed during pregnancy, is considered a non-stress test. But sometimes the situation requires a more careful and detailed study of the features of the work of a small baby heart, for example, with an unsatisfactory result of a previous CTG or if a child's heart defects are suspected, then stress tests are performed.

The study in this case is technically carried out in exactly the same way as always, but before attaching the sensors to the belly of the expectant mother, she may be asked to walk up and down the stairs several times, breathe deeply and occasionally hold her breath during cardiotocography.

Sometimes, in order to understand how the heart and nervous system of the child will behave in a stressful situation, a woman is given an injection of oxytocin, a drug that causes contractions of the uterine muscles.

A non-stress test excludes provoking external factors. A woman, on the contrary, is asked to calm down, to sit comfortably, not to think about anything disturbing and bad. It analyzes how the baby's heart reacts to his own movements, that is, the number of accelerations is counted.

Deciphering stressful CTG is the task of specialists, the conclusion of the analyzer program alone will not be enough, doctors will definitely make an adjustment for the stress factor. A good result is a negative non-stress test, during which the baby "shows" two or more accelerations in 40 minutes.

Possible problems

The problems that such an examination as cardiotocography can indirectly indicate can be different - from congenital malformations to pregnancy pathologies or external adverse factors to which the woman herself is exposed. But all of them will be accompanied by one of the following deviations.

Tachycardia

We can talk about such a state if the basic heart rate exceeds the established norms, and the duration of the demonstration of the violation is 10 minutes or more. An increase in heart rate to 160-179 beats per minute speaks of mild tachycardia. We are talking about a severe form of tachycardia when the baby's heart beats at a frequency of 180 beats per minute or more.

The most common cause is fetal hypoxia. With oxygen deficiency, the child begins to experience stress, his hormonal background changes, because of this, the heart begins to beat faster. But this is only at an early stage of hypoxia. With severe oxygen deficiency, the baby behaves differently.

Tachycardia is often a companion of an intrauterine infection that struck the baby. Almost like a newborn baby, the baby in mommy's belly can get sick. His immune defense will begin to work, and despite the fact that it is still very weak, the temperature will rise, and this will also immediately affect the heart rate. The cause of the child's tachycardia may also be the unimportant well-being of his parent. If a woman's temperature rises, then the child's heart beats faster.

Also, the fetal heart rate is affected by medications taken by his mother and any violations of her hormonal levels.

Bradycardia

If cardiotocography shows that the baby's heart beats at a rate of less than 100 beats per minute for 10 minutes or more, doctors diagnose bradycardia. This is a dangerous symptom that may indicate severe uncompensated hypoxia, in which oxygen deficiency is already critical, the child does not have the strength to move. If a slowdown in heart rate is recorded on CTG at the time of childbirth, then there is nothing dangerous in this, because the baby responds to the passage through the birth canal with a decrease in heart rate when its head is pressed.

Fetal hypoxia

Oxygen starvation can be very dangerous for a child at any time, it leads to CNS disorders, and sometimes to fetal death. Early hypoxia, while it is still compensated by the protective mechanisms of the baby's body, is characterized by tachycardia, and late hypoxia, hypoxia in the advanced stage - bradycardia. In addition, CTG shows low variability, the same periodic accelerations, sinusoidal rhythm, and monotony.

PSP in this state of affairs is in the range of 1.1 - 3.0. And according to Fisher, the child's condition is estimated at 5-8 points, depending on the severity of oxygen deficiency. In severe hypoxia, urgent delivery is indicated, regardless of how long the pregnant woman is - at 37 weeks or only at 33 weeks. In any case, such a baby will have more chances to survive outside the mother's womb.

Can it be wrong?

Cardiotocography does not apply to high-precision diagnostic studies. Its accuracy is about 90%, and a lot also depends on how correctly the examination was carried out, as well as on the experience of the doctor and whether he will be able to correctly interpret the results. In general, CTG stands for everyone in the same way. But the reasons that led to the deviations of certain normative values can be very diverse.

Therefore, it is impossible to treat the conclusion of the CTG as the ultimate truth. The survey gives only a general picture, but only additional diagnostics will help to confirm or refute the negative results, as well as to establish the reasons for the unusual behavior of the baby.

Usually these are laboratory blood tests, ultrasound scanning, UZDG (ultrasound with Doppler).

An erroneous CTG may be due to the fact that the woman did not prepare for the examination - she came sleepy, worries about personal problems. The doubtful veracity of CTG is also seen if the pregnant woman took any medication and did not warn the doctor about it, because some medicines can significantly increase and decrease the heartbeat of not only the mother, but also the fetus. An erroneous CTG may be in the event of a malfunction of the equipment on which the study is being carried out.

All doubtful results are therefore necessarily rechecked by repeated CTG, as well as with the help of ultrasound. All bad CTG results are also rechecked, but already in a hospital, so as not to risk the health of the mother and child.

Cardiotocography (CTG) is a method of simultaneously recording the fetal heart rate, as well as uterine tone. This study, due to its high information content, ease of implementation and safety, is performed by all pregnant women.

Briefly about the physiology of the fetal heart

The heart is one of the very first organs that is laid in the body of the embryo.

Already at the 5th week of pregnancy you can register. This happens for one simple reason: there are cells in the tissue of the heart that can independently generate an impulse and cause muscle contractions. They are called pacemakers or pacemakers. And this means that the work of the fetal heart on early dates pregnancy does not obey the nervous system at all.

Only by the 18th week of gestation, signals from the vagus nerve come to the heart, its fibers are part of the parasympathetic nervous system. Due to the influence of the vagus nerve, the heart rate slows down.

stages of fetal heart development

And by the 27th week, the sympathetic innervation of the heart is finally formed, which leads to an acceleration of heart contractions. The influence of the sympathetic and parasympathetic nervous systems on the heart is the coordinated work of two antagonists whose signals are opposite.

Thus, after the 28th week of pregnancy, the heart rate is a complex system that obeys certain rules and influences. For example, as a result of the motor activity of the baby, signals from the sympathetic department of the nervous system predominate, which means that the heart rate accelerates. Conversely, during sleep, the baby is dominated by signals from the vagus nerve, which leads to a slowing of the heart rate. Thanks to these processes, the principle of “unity of opposites” is formed, which underlies the myocardial reflex. The essence of this phenomenon lies in the fact that the work of the fetal heart in the third trimester of pregnancy depends on the motor activity of the baby, as well as the sleep-wake rhythm. Therefore, for an adequate assessment of the heart rhythm, these factors must be taken into account.

It is thanks to the peculiarities of the innervation of the heart that it becomes clear why cardiotocography becomes as informative as possible in the third trimester of pregnancy, when the work of the heart obeys certain rules and patterns.

How does a cardiotocograph work and what does it show?

This device has the following sensors:

Ultrasound, which captures the movements of the fetal heart valves (cardiogram);
Tensometric, which determines the tone of the uterus (tokogram);
In addition, modern heart monitors are equipped with a remote control with a button that must be pressed at the time of fetal movement. This allows you to assess the nature of the movements of the baby (actogram).

Information from these sensors enters the heart monitor, where it is processed and displayed on an electronic scoreboard in digital equivalent, and also recorded by a recording device on thermal paper. The tape drive speed differs by different types fetal heart monitors. However, on average, it is from 10 to 30 mm per minute. It is important to remember that there is a special thermal paper for each cardiotocograph.

an example of a CTG tape: at the top is the fetal heartbeat, at the bottom are the values of the uterine tone

How is cardiotocography done?

In order for this study to be informative, the following rules must be followed:

Recording of CTG is carried out for at least 40 minutes. It is during this time that certain patterns of rhythm changes can be traced.
The pregnant woman should lie on her side during the examination. If during the registration of CTG the pregnant woman lies on her back, then unreliable results may be obtained, which is associated with the development of the so-called inferior vena cava syndrome. This condition develops as a result of the pressure of the pregnant uterus on the abdominal aorta and inferior vena cava, as a result of which a violation of the uteroplacental blood flow may begin. Thus, when receiving signs of hypoxia on CTG, performed in the position of the pregnant woman lying on her back, it is necessary to redo the study.
The sensor that registers the fetal heartbeat must be installed in the projection of the back of the fetus. Thus, the place of fixation of the sensor depends on the position of the fetus in the womb. For example, with a head presentation of a baby, the sensor must be installed below the navel, with a pelvic presentation - above the navel, with a transverse or oblique - at the level of the umbilical ring.
A special gel must be applied to the sensor, improving the conduction of ultrasonic waves.
The second sensor (tensometric) must be installed in the fundus of the uterus. It is important to know that you do not need to apply gel on it.
During the study, the woman must be given a remote control with a button that must be pressed when the fetus moves. This allows the doctor to compare rhythm changes with the baby's motor activity.

Cardiotocogram indicators

The following indicators are the most informative:

What type of CTG during pregnancy is considered normal?

An ideal cardiotocogram is characterized by the following features:

Basal rhythm from 120 to 160 beats / min.

There are 5 or more accelerations during 40-60 minutes of CTG recording.

The rhythm variability is in the range from 5 to 25 bpm. in min.

There is no deceleration.

However, such an ideal version of CTG is rare, and therefore The following indicators are allowed as options for the norm:

The lower limit of the basal rhythm is 110 per minute.
There are short-term single decelerations lasting no more than 10 seconds and small in amplitude (up to 20 beats), after which the rhythm is completely restored.

When is CTG considered pathological during pregnancy?

There are several pathological variants of CTG:

Silent CTG the fetus is characterized by the absence of accelerations or decelerations of the rhythm, while the basal rhythm may be in the normal range. Sometimes such a cardiotocogram is called monotonous, the graphic image of the heartbeat looks like a straight line.
Sinusoidal CTG has a characteristic sinusoidal shape. In this case, the amplitude is small, equal to 6-10 beats. in min. This type of CTG is very unfavorable and indicates severe fetal hypoxia. In rare cases, this type of CTG may appear when a pregnant woman takes narcotic or psychotropic drugs.
lambda rhythm- this is an alternation of accelerations and decelerations immediately after them. In 95% of cases, this type of CTG is the result of compression (compression) of the umbilical cord.

In addition, there are many types of CTG that are considered conditionally pathological. They are characterized by the following features:

Presence of decelerations after accelerations;
Reduced motor activity of the fetus;
Insufficient amplitude and rhythm variability.

These signs may appear when:

entanglement of the umbilical cord;
The presence of the umbilical cord;
The presence of diseases in the mother. For example, in pregnant women with hyperthyroidism, thyroid hormones can cross the placental barrier and cause arrhythmias in the fetus;
Anemia of the baby (for example, when associated with immunological incompatibility of the blood of the mother and fetus);
Inflammation of the membranes (amnionitis);
Acceptance of certain medicines. For example, Ginipral, widely used in obstetrics, can cause an increase in the baby's rhythm.

What to do if the CTG indicators are borderline between the norm and pathology?

When registering a CTG and receiving a dubious result, you must:

Conduct additional research methods (ultrasound, study of blood flow velocity in the uteroplacental system, determination of the biophysical profile).
After 12 hours, repeat the study of CTG.
Avoid taking drugs that can affect the baby's heart rate.
Carry out CTG with functional tests:
1. Non-stress test - is to study the heart rate in response to fetal movements. Normally, after the baby moves, the rhythm should accelerate. The lack of acceleration after movements is an unfavorable factor.
2. Stress test - characterized by a change in heart rate after the introduction of 0.01 IU of oxytocin. Normally, after the intake of this drug in the body of a pregnant woman, the fetal rhythm accelerates, there are no decelerations, while the basal rhythm is within acceptable limits. This indicates a high compensatory capacity of the fetus. However, if, after the introduction of oxytocin, the fetus does not experience accelerations, but on the contrary, heart contractions slow down, then this indicates intrauterine hypoxia of the baby.
3. The mammary test is an analogue of the stress test, but instead of administering oxytocin, the pregnant woman is asked to massage the nipples for 2 minutes. As a result, the body releases its own oxytocin. The results are evaluated in the same way as in the stress test.
4. Test with physical activity- the pregnant woman is asked to climb the stairs of the 2nd floor, immediately after that a CTG recording is performed. Normally, the fetal heart rate should increase.
5. Breath holding test - while recording a cardiotocogram, the pregnant woman is asked to hold her breath while inhaling, while the baby's heart rate should decrease. Then you need to hold your breath while exhaling, after which the fetal rhythm should accelerate.

How is CTG evaluated in points?

To ensure that the interpretation of the results of CTG is not subjective, a convenient system for evaluating this type of study has been developed. The basis is the study of each indicator of CTG and the assignment of certain points to it.

For the convenience of understanding this system, all the characteristics of the CTG are summarized in the table:

	2 points	1 point	0 points
Basal (basic) rhythm	120 to 160	100 to 180	Less than 100, more than 180
Amplitude	6 to 25	3-5	< 3
Variability	> 6	3-6	< 3
The number of episodes of acceleration in 40 minutes	>5	1-4	missing
Decelerations	Not registered	short-term	Long, heavy
Fetal movements	>3	1-2	No

The interpretation of the results is evaluated as follows:

CTG is considered good if it scored 9-12 points;
A set of 6-8 points indicates signs of hypoxia, in such situations daily monitoring and treatment are required.
Less than 5 points is extremely unfavorable.

Important! Pronounced pathological changes on CTG may indicate the terminal state of the fetus. Of course, in such situations, no functional tests can be carried out categorically. In these cases, an emergency delivery may be required, as delay is very dangerous.

CTG during childbirth

The study of the heart rate is necessary both in the first (opening of the cervix) and in the second (pulling) period of labor. This is necessary in order to prevent acute intrauterine hypoxia, which threatens the life of the fetus and is an indication for an emergency caesarean section.

It is for this reason that the CTG recording must be started already at the first signs labor activity. With a normal birth, it is enough to register CTG every hour.

This study also shows:

After the outflow of amniotic fluid;
When conducting epidural anesthesia in childbirth (after the introduction of an anesthetic).

Permanent recording of CTG is necessary for conditions such as:

However, it should be remembered that CTG during pregnancy and childbirth is not the same thing. Therefore, the interpretation of the results must be approached differently. It is quite natural to ask: why is this happening?

The fact is that during the contraction, the muscle fibers of the uterus contract, which means that there is a spasm of the vessels located in the thickness of the myometrium. As a result, uteroplacental blood flow worsens and moderate fetal hypoxia develops. During this period, the baby's heartbeat may slow down or, conversely, be excessively fast. For this reason, the common phrase that “childbirth is stressful for a child” has a constructive explanation. However, after a contraction, placental blood flow is restored, and the heartbeat returns to normal. In this regard, clear criteria have been developed for assessing CTG during childbirth.

Normal indicators of the generic cardiotocogram are characterized by:

The heart rate is in the range from 110 to 160 beats per minute.
The presence of at least two episodes of rhythm acceleration (accelerations) lasting more than 15 seconds during the CTG recording period.
The presence of rhythm variability from 5 to 25 beats min.
After the opening of the cervix by more than 4-5 cm, early decelerations lasting no more than 30 seconds are allowed.

CTG is considered doubtful if the following signs are present:

The rhythm is in the range from 100 to 110, or from 160 to 170 beats per minute.
Within an hour there is not a single episode of acceleration of the heart rate.
Low variability (less than 5 bpm).
There are rhythm slowdowns that last from 30 to 60 seconds.

Pathological CTG is characterized by:

Too slow (less than 100 beats per minute) or too fast (more than 170 beats per minute) rhythm.
Prolonged episodes of deceleration, lasting more than 1 minute.
Lack of variability, in other words, a monotonous rhythm.
The so-called sinusoidal nature of CTG, when the heartbeat graph resembles a sinusoid.

How does CTG affect medical tactics?

The results of the study must be taken seriously. The doctor who evaluates CTG has a great responsibility. It is for this reason that each film with the registration of cardiac activity must be evaluated by the responsible doctor, certified by his signature indicating the time of the study and glued to the birth history.

A normal cardiotocogram is a sign of the correct and careful management of childbirth.

Upon receipt of a dubious CTG, the doctor has no more than 40 minutes to correct labor activity. At this stage, it is necessary to eliminate all risk factors leading to hypoxia:

Poor CTG is a good reason to change the tactics of delivery in favor of an emergency caesarean section, or to eliminate the causes of acute hypoxia. Ignoring pathological CTG is absolutely unacceptable, because it can cause fetal death.

In other words, CTG is a serious tool in the hands of an obstetrician.

conclusions

Cardiotocography is rightfully one of the most widely used studies in obstetrics. However, like any other technique, it is effective only if it is applied correctly (in accordance with all norms), as well as when the results are correctly deciphered.

Unfortunately, there are still disputes and discrepancies in some complex and dubious cases. For this reason, do not forget that there are also additional research methods that can either confirm or refute possible fears.

In addition, the results of CTG remain relevant and informative for no more than 1 week, which means that the key to a favorable course of pregnancy is regular monitoring of the fetus.