Why do CTG pregnant. Deciphering CTG during pregnancy. How necessary is CTG for pregnant women?

Cardiotocography is a study that is carried out only in pregnant women. The procedure is completely harmless to the baby and generally does not affect the course of pregnancy. It is prescribed to assess the fetal cardiac activity and identify possible disorders, including such a dangerous condition as hypoxia - a lack of oxygen.

In order to properly prepare for the study, you need to know what CTG is during pregnancy and how it is done.

CTG - what is it

At a routine examination, pregnant women measure the baby's heart rate with an obstetric stethoscope. However, this method is not enough to determine any cardiac disorders or fetal hypoxia. If such pathologies are suspected, the doctor directs the woman to a more complete examination of the baby's heart - CTG.

Pregnant women are usually interested in each procedure, as they are worried about the unborn child. Accordingly, to learn about CTG during pregnancy - what it is and why, the normal desire of every mother who receives such a referral.

With the help of cardiotocography, the heart rate of the child is measured, taking into account the effect of uterine contractions on it. And also fix his movements in the womb. Evaluation of all parameters allows you to determine how the child reacts to a particular impact.

The procedure is most indicative from the 32nd week of pregnancy. If there are indications, it can be done earlier - from the 28th week, but the result in this case should be evaluated in conjunction with other studies - dopplerography and ultrasound. This is due to the fact that in the early stages the child's heartbeat may not be heard by the device. Among other things, in the third trimester, the fetus develops distinct phases of sleep and activity, which is also important.

If the pregnancy is proceeding normally, CTG may be prescribed 2 to 3 times for the entire period before delivery. If hypoxia or other disorders of the child's heart are suspected, the study is carried out every 7 to 10 days. If a pathology is detected according to previous results, as well as when you are in a hospital for any indication, the measurement is performed daily.

During childbirth, CTG is a mandatory procedure. It is carried out every 3 hours if the period of contractions proceeds normally. In cases where any complications are identified, the doctor prescribes additional CTG in order to take timely measures for emergency delivery if necessary.

How is the procedure carried out

CTG lasts from 20 to 40 minutes, depending on the timing and initial results. During childbirth, the study is carried out for 5 contractions. The measuring device is equipped with two sensors:

Ultrasound, as with conventional ultrasound, measures the baby's heart rate.
Tensometric - fixes uterine contractions.

Older models are additionally equipped with a remote control with a button that must be pressed when the woman feels movement. Modern devices record the movements of the child independently.

The study is carried out in the supine position, sitting or reclining. Lying horizontally on the back is not recommended, as this can compress the umbilical cord, which negatively affects the child and, as a result, the results. Sensors are attached to the abdomen with special straps. Ultrasound - in the place where the heart of the child is best heard, and tensometric - in the upper abdomen.

What CTG shows depends not only on the real condition of the child, but also on other factors. The best time intervals for research:

in the morning - from 9 to 14 hours;
in the evening - from 19 to 24 hours.

If CTG is performed at a different time, and any deviations are revealed, before drawing conclusions, it is necessary to repeat the procedure, taking into account this condition.

How to prepare

Special preparation for CTG is not required. You do not need to take anything with you to cardiotocography, except for a diaper, which will need to be placed on the couch where the study will be carried out. It is advisable not to eat before the procedure, but you should not be hungry either. It is optimal if the meal was 1.5 - 2 hours before it. The fact is that the child reacts to changes in the amount of glucose in the mother's blood, and this can blur the results. In extreme cases, if a woman is hungry, you can eat a chocolate bar.

Be sure to take into account that during pregnancy, the urge to go to the toilet occurs quite often, so you need to empty the bladder before CTG so that you do not have to interrupt the study.

When CTG is done, stress and other emotional upheavals can negatively affect the results, so you need to go to the procedure in a calm state. The child is very sensitive to changes in the mother's mood and may be overly active.

Deciphering the results

The conclusion on the CTG schedule is based on the following parameters:

Basal heart rate is the average value of the fetal heart rate. This parameter is normally 120 - 160 beats / min.
Heart rate variability is the number of amplitude changes in the basal heart rate over a period of time. The norm of CTG is from 6 oscillations (changes up or down) in 1 minute.
Accelerations - increased heart rate by 15 beats / min or more for 15 seconds. Their number is estimated. The norm is more than 2 accelerations in 10 minutes.
Deceleration - decrease in heart rate by 15 beats / min or more for 15 seconds. In the normal state of the fetus should be absent or be insignificant and rare.
The amplitude of heart rate oscillations is the average value of deviations from the basal heart rate. Should be within 5 - 25 beats / min.

For the convenience of evaluating the results, it is customary to evaluate each of the parameters from 0 to 2 points. The higher the number, the better. The scores are added together to get the overall study score.

Depending on the number obtained, the results are interpreted as follows:

8 - 10 points. Normal indicators, violations are not revealed.
6 - 7 points. Signs of hypoxia in the fetus were found. To clarify the diagnosis, it is necessary to repeat the CTG and undergo an additional examination - Doppler and ultrasound.
5 points or less. Immediate hospitalization is required, as serious violations of cardiac activity have been identified. In a hospital, the cause of the deviations is determined, intensive therapy is carried out and, if necessary, urgent delivery.

The scoring of the study is carried out by the attending physician, then the result is reported to the patient. To obtain reliable data, it is important to observe the conditions for time and food intake. And also you need to understand whether the child is awake at the time of the procedure. Usually pregnant women themselves can determine this without much difficulty, based on their feelings.

If the fetus is in the sleep phase, CTG will definitely be “bad”, which can mislead the doctor and the woman about the baby’s health.

The cardiotocogram is an important and revealing study. However, it must be remembered that final conclusions cannot be drawn from the results of CTG alone. Assessment of the child's condition and his cardiac activity is carried out in a complex with other planned and additional examinations.

Self-evaluation of the results will help you orient yourself and allow you to see the big picture. But decoding must be carried out by a doctor, based on his experience and knowledge.

Many pregnant women are concerned about the question: fetal CTG - what is it? This is cardiotocography, which is a safe method for examining the fetus during pregnancy. Thanks to this method, doctors can determine the absorption of oxygen, physical endurance in the form of heartbeats and their changes.

Doctors perform fetal CTG during pregnancy, as well as during childbirth, when the baby passes through the birth canal. And the results of CTG show how the child's condition is assessed.

How is fetal CTG done?

What does fetal CTG mean? For women facing this procedure for the first time, information about it will be useful and interesting. First of all, you need to understand how fetal CTG is done. During the study of the fetal heartbeat, ultrasound sensors are placed on the woman's abdomen.

The signal generated by the sensor is sent to the child's heart, and returns back with the fixation of heart beats on the heart monitor. CTG indicators are calculated by the number of beats per minute. All changes are fixed by digital graphic images.

It is impossible that the study was carried out immediately after a meal or, conversely, on an empty stomach, since the sugar level can distort the results. Also, during the diagnosis, a woman should feel comfortable.

Why is fetal CTG needed?

In addition to the fact that CTG allows you to obtain data on the fetal heartbeat and is an extended version of the cardiogram, this type of examination also reveals other abnormalities in the development of an unborn child.

The pathologies determined by CTG include:

hypoxia;
intrauterine infections;
rapid maturation of the placenta;
fetoplacental insufficiency;
anomalies of the cardiovascular system.

Usually you have to do a fetal CTG only twice during pregnancy, but doctors, if they suspect a deviation in the normal course of pregnancy, may prescribe an additional examination. Fetal CTG is normally performed weekly after the 30th week of pregnancy.

Deciphering cardiotocography

Interpreting survey data is no less important than the survey itself. An experienced doctor can even see the initial violation of the fetus on special charts, but sometimes CTG scores are given, which is more accessible and understandable for pregnant information.

In any case, the expectant mother should be able to understand at least a little the norm of cardiotocography and deviations from the norm. When deciphering, the basal rhythm, amplitude, acceleration, or, conversely, a reduction in heart rate, are taken into account. Each parameter is determined in points from 0 to 2. And at the final stage of decoding, the points are added up, and their total number determines the violation of the fetal condition.

If there are a total of 5 points or less, then the pregnant woman urgently needs hospitalization. If 6-7 points, then the woman undergoes mandatory additional examinations to exclude possible pathologies. An ultrasound is performed, other studies that will determine the movement of the fetus, its activity, and sufficient placental nutrition. If there are 8-10 points, then this indicator is the norm and indicates the normal health of the child and a well-running pregnancy.

An important indicator is the basal rhythm - it should be from 110 to 160 beats. The doctor will not be interested in the maximum and minimum indicators on the graph. Average values are important. Graphs are easy to understand on your own.

It is necessary to move the graph to the distance of an outstretched arm, draw a conditional straight line along the graph with a finger. The basal rhythm will be the line of the vertical axis, which corresponds to the conducted level.

Another indicator is variability. It should be 5-25 strokes. If the frequency of strokes is less, then this indicates a short gestational age or that the baby is at rest. Although this may be a reason for additional examination. With a high frequency of strokes, fetal hypoxia is possible due to entanglement with the umbilical cord.

The rhythm, the number of accelerations, decelerations are also determined, but only medical workers can decipher these indicators. According to them, an indicator of the condition of the fetus is determined. If this indicator is less than 0.8, then you should not worry about the condition of the child. The procedure is completely safe, so the expectant mother does not need to worry about anything.

Cardiotocography (CTG)

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 an effective research method to exclude 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).
Violations in the child that were previously found with (developmental delay, disturbances in the amniotic fluid, decreased 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 its nervous system, although 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 is undoubtedly 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.
The presence of different types of 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.

Cardiotocography (CTG) is a prenatal diagnostic method that allows you to determine the condition of the fetus and how the uterus is functioning. In combination with ultrasound and dopplerography, cardiotocography allows you to effectively and quickly identify pregnancy pathologies and take the necessary measures to correct them.

As a rule, CTG is performed after 32 weeks. At this time, the fetus already lives in a certain rhythm of sleep and activity, and the beating of his heart is clearly audible. However, sometimes cardiotocography is prescribed at an earlier date, since pathological rhythms can be determined after 20 weeks.

The most popular question related to this procedure, which is often asked by future parents - what is the norm of CTG during pregnancy? Most often, the first time pregnant women are sent for cardiotocography at 34 weeks (35 weeks). Women are very interested in what each word means in conclusion, how many points are considered the norm and when to sound the alarm.

Informative indicators

When deciphering cardiotocography, the following rhythm indicators are taken into account:

Basal (basic) rhythm- it prevails on CTG. In order to objectively evaluate it, it is necessary to record at least 20 minutes. We can say that the basal heart rate is an average value that reflects the heart rate of the fetus during the rest period.
Variability (variability)- this is the dynamics of heart rate fluctuations relative to its average level (the difference between the main heart rate and rhythm jumps).
Acceleration (acceleration of the heart rate)- this parameter is taken into account if for 10 or more seconds there are more than 15 hits. On the chart, they are represented by tops facing upwards. As a rule, they appear during the movements of the baby, uterine contractions and the performance of functional tests. Normally, at least 2 accelerations of the heart rate should occur in 10 minutes.
Deceleration (slow heart rate)- this parameter is taken into account in the same way as acceleration. On the graph, these are the teeth looking down.

The duration of decelerations can be different:

up to 30 seconds, followed by the restoration of the fetal heartbeat;
up to 60 seconds with high amplitude (up to 30–60 beats per minute);
more than 60 seconds, with a high amplitude of oscillation.

In addition, in the conclusion there is always such a thing as signal loss. This happens when the sensors temporarily lose the sound of the baby's heartbeat. And also in the diagnostic process they talk about the reactivity index, which reflects the ability of the embryo to respond to irritating factors. In deciphering the results, the fetal reactivity index can be assigned a score in the range from 0 to 5 points.

In the printout, which is issued to the hands of a pregnant woman, the following 8 parameters are prescribed:

Analysis time/signal loss.
Basal heart rate.
Accelerations.
Decelerations.
Variability.
Sinusoidal rhythm/amplitude and oscillation frequency.
Movement frequency.

With an absolute norm, 8 out of 8 parameters must be observed. Depending on which parameters were not met, experts allow 7 out of 8 and 6 out of 8 parameters to be normal. However, in this case, you can not do without re-conducting CTG. The heart rate range is displayed on the cardiotocogram (two digits are indicated).

During recording, the calibration tape displays a graph of two types of signal

Evaluation points

In the process of developing cardiotocography, experts have identified objective criteria for evaluating the recording and compiled many tables. Several scales are used to interpret CTG results. Most often resort to the Fisher scale (10 points) or Krebs (12 points). In conclusion, they may indicate a double result - a score according to fischer and krebs.

Fisher criteria

The evaluation table, developed by an American obstetrician-gynecologist, presents a number of criteria that are rated from 0 to 2 points. The final score is set by summing up all the marks. According to Fisher, experts conduct a "manual" calculation, focusing on what they see on the calibration tape.

After evaluating the criteria, there are 3 main conditions of the fetus:

Normal indicators are 8–10 points. The baby's heart beats well and he is moderately mobile, and there are no suspicions of oxygen starvation.
A state of doubt - 5–7 points. Such a result may indicate the initial stage of oxygen starvation and requires special monitoring of the pregnant woman.
Poor condition of the fetus - 0-4 points. This indicates severe hypoxia. If you do not take urgent measures, then a fatal outcome for the baby may occur within a few hours.

If the CTG recording gives a result of 7 or 6 points, then repeat cardiotocography is prescribed within 12 hours, and if labor has begun, then after 1 hour. In the event that the CTG recording had a score of 8 or more points, then with the onset of childbirth, the procedure is repeated after 2–3 hours, and at earlier times the pregnant woman is released for 3–7 days before the second CTG.

Krebs scale

This rating scale differs from the Fisher scale by one criterion - the number of motor reactions of the baby in 30 seconds: if they are completely absent, 0 points are set, from 1 to 4 motor reactions are estimated at 1 point, if there are 5 or more reactions in 30 seconds, then they give 2 points.

In view of this criterion, the Krebs scale has a 12-point evaluation system. If as a result, on this scale, from 9 to 12 points were set, then future parents can be absolutely calm - the results are within the normal range. A score from 0 to 8 points is a reason to sound the alarm. With such results, they speak of the presence of a pathological intrauterine process.

If there are 11 points in the CTG conclusion, then there is no doubt that the Krebs scale was used in decoding. If the score is 9 points, then the result is considered good in any scenario. But if there was no postscript that the assessment was carried out according to Fisher, then you should still additionally consult a specialist.

Dawes-Redman criteria

These criteria have been developed for automatic devices. The computer evaluates the record without the participation of a diagnostician, but taking into account all the same parameters as in the "manual" method.

As a result, all significant CTG criteria are summed up and a special indicator of variability, STV, is displayed. This sensitive parameter makes it possible to detect signs of fetal suffering and predict an unfavorable pregnancy outcome.

According to Dawes-Redman, the following results are distinguished:

normal indicators indicating a healthy pregnancy - STV 6–9 ms;
boundary indicators that require specialist supervision - STV 3–5 ms;
high risk of oxygen deficiency requiring emergency measures - STV 2.6–3 ms;
critical condition of the fetus, which in the next few hours may result in intrauterine death - STV less than 2.6 ms.

This assessment system is not practiced in the process of labor that has begun, but is successfully used for monitoring during the period of bearing a child. As a rule, CTG is recorded every 2–3 weeks at 28–32 weeks and every 2 weeks at 32–37 weeks. And after 38 weeks they resort to CTG every 7 days.

Frankly poor and questionable CTG results can be a serious reason for an emergency caesarean section.

The results are evaluated by the leading obstetrician-gynecologist

Indicators of the state of the fetus

After evaluating the CTG indicators, doctors determine the value of PSP (an indicator of the condition of the fetus). There are 4 standard conclusions on PSP. Below 1.0 - normal indicators (sometimes repelled from 1.05). At the same time, if borderline indicators were obtained - 0.8-1.0, then the recording is recommended to be repeated within 1-2 weeks.

From 1.05 to 2.0 - primary deviations. Such a conclusion requires therapeutic measures and a control recording of CTG within a week. From 2.01 to 3.0 - severe deviations. In this case, the woman is recommended a hospital for taking measures to preserve the pregnancy. PSP of 3.0 or more - a critical condition of the fetus. The pregnant woman should be urgently hospitalized, most likely, an emergency delivery will be indicated.

CTG normally does not differ much from 33 weeks to 36 weeks and is characterized by the following features: the main rhythm is from 120 to 160 beats / min, within 40–60 minutes there are from 5 accelerations of the heart rate, the range of variability is from 5 to 25 beats per minute. minute, there is no slowing of the rhythm.

The use of CTG in childbirth (38 weeks - 40 weeks) is determined individually. Fetal CTG during this period can give the following results:

Moderate amplitude of heart rate slowdowns: basal rhythm - 160–180 beats/min, range of variability - more than 25 beats/min, early slowdowns of the rhythm - less than 30 beats/min, late - less than 10 beats/min, pronounced acceleration of the heart rate. With such indicators, childbirth should proceed naturally without the intervention of obstetricians.
The state is on the verge of risk: the main line of CTG is from 180 beats per minute, the variability of the curve is less than 5 beats / min, early slowing of the rhythm is 30–60 beats / min, late - 10–30 beats / min. In this case, natural delivery is not excluded, but the Zading test is additionally performed. After that, obstetricians take all the necessary manipulations to achieve natural childbirth, but if all the steps taken are ineffective, then the woman in labor is prepared for a caesarean section.
Dangerous condition: the main line does not exceed 100 beats per minute, early heart rate slowdowns exceed 60 beats / min, late ones exceed 30 beats / min. The actions of obstetricians in this case do not differ from those that are carried out in risky conditions of the fetus.
Critical state of the fetus. There is a pronounced increase in heart rate with residual decelerations, which can last up to 3 minutes. The graphic curve is flattened. The situation does not tolerate delay, it is urgent to perform a caesarean section.

If questionable results are obtained, a second CTG is performed after 12 hours.

High-amplitude decelerations lasting more than 1 minute indicate severe oxygen starvation.

Pathological CTG

There are 3 pathological variants of CTG.

Silent or monotonous CTG

It is characterized by the absence of accelerations and decelerations, but at the same time, the basal heart rate is within the normal range. The graphic representation of such cardiotocography is close to a straight line.

Sinusoidal CTG

The graphic representation of such cardiotocography has the form of a sinusoid. Such CTG indicates a pronounced oxygen starvation of the fetus. Sometimes it is found against the background of a pregnant woman taking psychotropic drugs or drugs.

lambda rhythm

It is characterized by a rapid alternation of accelerations and decelerations. In most cases, this pathology of CTG indicates compression of the umbilical cord. As a rule, it is pinched between the fetal head and the maternal pelvic bones, which leads to a decrease in blood flow and the development of hypoxia.

In addition, conditionally pathological types of CTG are distinguished with characteristic features: the presence of decelerations immediately following accelerations, passivity of movements in the fetus, insufficient range and rhythm variability.

Upon receipt of doubtful results with standard CTG, a recording is made with functional tests:

Non-stress test. Heart rate studies are performed against the background of natural fetal movements. In a normal state, after any movement of the child, the heart rate should accelerate. If this does not happen, then we can talk about the presence of pathology.
stress test. A pregnant woman is injected with oxytocin and monitors changes in the baby's heart rate. Normally, accelerations should be observed, the basal rhythm should be in the acceptable range, and there should be no decelerations. If, after the introduction of this drug, the fetus does not experience acceleration of the rhythm, but rather it can be noted that the heart contractions slow down, then this indicates oxygen starvation.
Mammary test. During this test, the production of natural oxytocin in the woman's body is achieved by massaging the nipples for 2 minutes. Further, an assessment is made, as in the case of the introduction of synthetic oxytocin.
Exercise test. CTG is recorded immediately after the pregnant woman performs a series of actions that involve physical activity. Most often, she is asked to climb the stairs to 2 flights of stairs. In response to such actions, the fetal heart rate should increase.
Breath test. A pregnant woman in the process of recording CTG should hold her breath, first on inspiration, and then on exhalation. In the first case, it is expected that the baby's heart rate will decrease, and in the second it will increase.

Unlike standard ultrasound and Doppler ultrasound, which demonstrate the anatomy and circulation of the fetus and child's place, CTG allows you to determine the effect of oxygen and nutrients on the child. In addition, CTG is indispensable in the process of delivery, when other methods cannot be applied. Such a study helps to choose the right tactics for conducting childbirth, taking into account how the fetus tolerates the loads that have appeared.

Monitoring the condition of the fetus is an important goal of examining a pregnant woman. It can be carried out in different ways. Cardiotocography is the most common, painless and affordable method of instrumental condition monitoring.

Cardiotocography is a technique for assessing the state of the fetus developing in the womb, which consists in analyzing changes in the frequency of its heartbeats at rest, during movements, and also in response to external factors.

Devices for conducting this study - cardiotocographs - are available in all antenatal clinics and maternity hospitals.

The methodology of this study is based on the well-known Doppler effect. The hardware sensor creates special ultrasonic waves that go inside the body and are reflected from the surface of media with different sound conductivity, after which they are fixed again by it. When the interface between media is shifted, for example, when moving, the frequency of the generated and received ultrasonic waves becomes different. The time interval between each heartbeat is the heart rate (HR).

Why pregnant CTG?

The purpose of the CTG is the timely detection of abnormalities in the functional state of the fetus, which allows the doctor, if any, to select the necessary therapy, as well as choose the appropriate timing and method of delivery.

Preparation
No special preparation is needed for this study.. But to obtain reliable results during the study, the woman must be relaxed and in a comfortable position, not to move. Therefore, before the procedure, you should go to the toilet in advance.

It is recommended that you eat approximately 2 hours before the test and should not be done on an empty stomach. By agreement with the doctor during the procedure, small snacks with something sweet are allowed if the baby is in the sleep phase in order to activate it. To do this, you can pre-purchase sweet food.

You should not take painkillers and sedatives 10-12 hours before the examination.

Methodology

During the study, the expectant mother takes a position on the couch lying on the right or left side of the body or half-sitting, leaning on a pillow. Special meters are fixed on her stomach - a gel is applied to one and fixed in the place where the fetal heart beat is best felt, the other sensor, which registers excitations and contractions, is placed in the area of the projection of the right angle or the bottom of the uterus. The patient independently marks the periods of fetal movement using a button for registering fetal movements.

Monitoring is carried out for at least half an hour to get the most accurate information about well-being. This duration of the study is explained by the frequent alternation of the phases of sleep and wakefulness in the child.

Decryption

Unlike many other research methods, the decoding of CTG at 32, 33, 34, 36, 37, 38, 39 and 40 weeks does not have any significant age-related nuances. There is a slight tendency to decrease the average fetal heart rate from 32, 33, 34 to 38 weeks.

Fetal movements on a cardiotocogram

One of the components of CTG recording is currently actography - recording fetal movements in the form of a graph. There are two ways to evaluate a child's movements. Mom can independently count the movements of the fetus that she feels. Or many modern devices are able to record movements themselves using a sensor. The second registration method is considered more reliable. At the same time, the movements look like high peaks on the actography graph.

The fetus moves almost constantly, except for periods of its sleep. According to CTG data, during 32.34, as well as 35-40 weeks of a normally developing pregnancy, the fetal motor activity generally increases. At 34 weeks, an average of 50 - 70 movements per hour are noted. After 34 weeks, an increase in the number of movements is recorded. So, from 60 to 80 movements per hour are recorded. The average duration of episodes of perturbations is 3-4 seconds. Gradually, with the growth of the fetus, it becomes more crowded in the uterine cavity, so closer to it it becomes calmer.

Contractions on cardiotocogram

In addition to the fetal heart rate and its movements, CTG can register contractile movements of the uterus, that is, contractions. Recording contractions on CTG is called a tokogram and is also displayed as a graph. Normally, the uterus reacts to the movements of the fetus in it with its contractions (contractions). At the same time, a decrease in the child's heart rate is recorded on CTG in response to uterine spasms. Contractions are the main sign of upcoming labor. Based on the tokogram, the doctor can determine the strength of the contraction of the muscular layer of the uterus and distinguish false contractions from true ones.

Based on the foregoing, it can be seen that CTG is a very important examination of the state of the developing fetus in the womb, which allows you to obtain information about the state of the heart rhythm, movements, and even evaluate contractions. Any deviations in CTG require a thorough cumulative analysis by a competent specialist in order to take the necessary measures that can save the life of a little man. All these properties make CTG an indispensable type of examination.