CTG conclusion during pregnancy. Interpretation of CTG during pregnancy. Indications for cardiotocography

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

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

Equipment for 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 are directed into the body and reflected from the surface of media with different sound conductivity, after which they are recorded again by it. When the interface between media shifts, for example, when moving, the frequency of the created and received ultrasonic wave becomes different. The time interval between each contraction of the heart is the heart rate (HR).

• Why do pregnant women need CTG?

  The purpose of CTG is to timely identify deviations in the functional state of the fetus, which allows the doctor, if any, to select the necessary therapy, as well as to 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, without moving. Therefore, before the procedure, you should go to the toilet in advance.

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

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

  Methodology

  During the examination, 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 - gel is applied to one and fixed in the place where the fetal heartbeat 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 fundus of the uterus. The patient independently notes the periods of fetal movement using a button to register fetal movements.

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

  Decoding

  Unlike many other research methods, decoding CTG at 32, 33, 34, 36, 37, 38, 39 and 40 weeks does not have any significant age-related nuances. There is a slight trend towards a decrease in 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 assess a child's movements. The mother can independently count the movements of the fetus that she feels. Or many modern devices are capable of recording movements themselves using a sensor. The second registration method is considered more reliable. In this case, the movements appear on the actography graph as high peaks.

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

  Contractions on a cardiotocogram

  In addition to the fetal heart rate and its movements, CTG can record contractile movements of the uterus, that is, contractions. The recording of contractions on CTG is called a tocogram and is also depicted 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 impending labor. Based on the tocogram, the doctor can determine the force of contraction of the muscular layer of the uterus and distinguish false contractions from true ones.

  Based on all of the above, it is clear that CTG is a very important examination of the condition 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 on CTG require a thorough cumulative analysis by a competent specialist in order to take the necessary measures that can save the life of the little man. All these properties make CTG an indispensable type of examination.

Often, expectant mothers are prescribed a CTG procedure. What is it and what is it for? Cardiotocography (CTG) is a safe, non-invasive way to functionally study the unborn baby during pregnancy, allowing you to assess the condition of the child through registration and subsequent analysis of its heartbeat. The study determines the fetal heart rate at rest, during motor activity (movements), as well as during uterine contractions and the influence of certain external factors. CTG is used not only during gestation, but also during delivery to assess the condition of the child passing through the birth canal.

What is cardiotocography?

Cardiotocography is an important diagnostic procedure, along with fetal ultrasound and Doppler blood flow, performed during pregnancy.

The cardiotocragram obtained as a result of the procedure is a recording of the baby’s heartbeat with simultaneous registration of uterine contractions. Decoding cardiotocography allows you to assess the baby’s cardiac activity and the nature of its reactivity, i.e. the ability to change and adapt heart rate to changing environmental conditions.

There are two types and, accordingly, methods of conducting cardiotocography:

1. external or indirect;
2. internal or direct.

Indirect CTG during pregnancy allows you to assess the nature of uterine contractions, as well as the rhythm of the baby’s heartbeat (heart rate and related indicators) through the belly of the expectant mother. An ultrasound sensor is used to record the child’s heart rate, and a special pressure transducer is used to assess uterine tone, in particular to measure uterine contractility. The external CTG method is simple and has no absolute contraindications. Used both during pregnancy and childbirth.

The internal CTG method is not actually used during pregnancy and can only be used during childbirth. The fetal heart rate is recorded using an electrocardiographic electrode attached to the baby's head, while intrauterine pressure is assessed either using a strain gauge or by inserting a special catheter into the uterine cavity.

Data obtained from CTG during pregnancy allow us to judge the presence of signs of oxygen starvation of the fetus (hypoxia), which directly affects the baby’s adaptive capabilities to signals and environmental conditions transmitted to him through the expectant mother. Oxygen deficiency causes inhibition of the child’s development and growth and increases the risk of complications both during labor and after childbirth.

When should research be conducted?

CTG during pregnancy can be done as early as 28-30 weeks of gestation, but obtaining a truly high-quality recording of diagnostic results is possible only after 32 weeks. It is during this period of time that the child’s motor activity acquires “phase”, i.e. begins to be regularly replaced by resting phases, which means the “activity-sleep” cycle is already fully established. The approximate duration of fetal sleep at this time is about half an hour, which should be taken into account both when conducting diagnostics and when describing the results.

How often can CTG be performed during pregnancy? It all depends on the condition of the mother and baby:

• In case of uncomplicated, favorable course of gestation, examination is carried out no more than once every 8-10 days.
• In the case of complicated gestation, in combination with normal data from previous examinations, cardiotography is done once a week or every 5 days, also, if necessary, for any changes in the pregnant woman’s well-being.
• In case of oxygen deficiency, diagnostics are carried out every day (or once every 2 days) until the symptoms of hypoxia are eliminated or until unplanned delivery, if necessary. Intrapartum (labor) cardiotocography is carried out at intervals of 2-3 hours in the first stage of labor, and under continuous CTG control in the second.

The most favorable time of day for cardiotocography is the biological and physical activity of the fetus, which it exhibits during the day - from 9.00 to 14.00, and in the evening - from 19.00 to midnight.

It is not advisable to carry out the procedure on an empty stomach. At the same time, the last meal is allowed 1.5-2 hours before the study. If all these “preparatory” factors are not met, and during the study deviations from the norm are noted, the diagnosis should be carried out again, taking into account all the rules. This is necessary because the baby is entirely dependent on the mother’s well-being, and the level of glucose in her blood (associated with food intake) can affect his activity, and choosing the wrong time can reduce the fetus’s responses to signals coming from the external environment.

CTG diagnostic technique

To conduct a classic CTG during pregnancy using an external method, the expectant mother is located on the couch, taking a position lying on her side or semi-sitting. The choice of position largely depends on the position in which the fetal heart rate (HR) is best heard. Lying on your back, the examination, as a rule, is not carried out, since the uterus can partially compress the blood flow in the main arteries, and the results of the examination will not be reliable.

How is CTG done? To begin with, the doctor uses a phonendoscope to assess the area of ​​the woman’s abdomen where the baby’s heartbeat is most audible. It is in this place that the ultrasound probe is applied. A special pressure sensor, designed to assess the tone of the uterus, is installed in the area of ​​the uterine fundus. On average, the recording time of a cardiotocogram ranges from 40-50 minutes. It is important to note that if satisfactory indicators are registered, the duration of the examination can be reduced to 20 minutes.

During childbirth, this procedure is carried out for at least 20 minutes, or over 5 contractions. Of course, these time intervals are arbitrary: if the condition of the expectant mother and baby changes, the duration of the examination procedure can be increased or decreased as prescribed by the doctor.

Standard cardiotocographic examination can be of two types:

1. Non-stressful method of examination.
   • A non-stress test involves recording the child’s heart rate without any external influence, i.e. in its natural conditions of existence. During the procedure, the baby's movements are recorded and noted on a cardiotocogram.
   • Registration of fetal movements occurs indirectly through measurement of uterine tone. This method is used if there is no sensor that records the child’s movements.
2. A stress test, using functional tests, is carried out as an additional diagnostic test if the results of non-stress cardiotocography are not good enough.

Interpretation of CTG results

In order to carry out an objective and high-quality assessment of the condition of the fetus, various normal indicators have been developed, including:

• basal rhythm (level) of heart rate (HR) is the average heartbeat rhythm that persists for 10 minutes or between contractions;
• variability of the basal heart rate - changes in heart rate and heartbeat amplitude;
• acceleration - a short-term (about 15 seconds) increase in heart rate by 15 beats per minute;
• deceleration - a short-term (about 10-15 seconds) decrease in heart rate by 15 beats per minute or more.

Decoding the cardiotocogram demonstrates the following results:

• basal heart rate rate: 120-160 beats per minute;
• norm of basal heart rate variability: 5-25 beats per minute;
• acceleration rate: 2 or more are observed during 10 minutes of study;
• rate of deceleration: absent, registration of very short and insignificant intervals of heart rate deceleration is possible.

For the convenience of calculating all indicators, a special scoring system for deciphering the results has been developed:

Final results of CTG in 8-10 points reflect the norm - the favorable state of the baby. Kit 5-7 points speaks of possible hypoxia - oxygen starvation of the fetus. In this case, an additional non-stress test is necessary, and in case of unsatisfactory results, the use of functional tests. In addition, it is recommended to carry out Doppler testing of the fetus (assessment of blood flow in the vascular system connecting mother and baby) and ultrasound of the pregnant woman.

Result below 4 points is very different from the norm and indicates severe hypoxia and the unsatisfactory condition of the baby. In this case, either an emergency delivery is performed, or special treatment and rehabilitation measures are prescribed to improve the well-being of mother and child.

Cardiotocography data is an important component of a comprehensive assessment of the child’s condition, but this study should not be carried out in isolation from other diagnostic procedures and examination of the pregnant woman. Only on the basis of deciphering all the examination results can we talk about prescribing a treatment plan and method of delivery.

Cardiotocography (CTG) is a prenatal diagnostic method that allows you to determine the condition of the fetus and how the uterus functions. In combination with ultrasound and Doppler ultrasound, 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 stage, the fetus already lives in a certain rhythm of sleep and activity, and the beating of its heart is clearly audible. However, sometimes cardiotocography is prescribed at earlier stages, since pathological rhythms can be determined after 20 weeks.

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

Informative indicators

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

• Basal (basic) rhythm- it predominates on CTG. To evaluate it objectively, it is necessary to record for at least 20 minutes. We can say that the basal heart rate is an average value that reflects the fetal heart rate during the resting 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 surges).
• Accelerations (increasing heart rate)- this parameter is taken into account if within 10 seconds or more there are 15 more beats. On the graph they are represented by the tops facing up. As a rule, they appear during the baby’s movements, uterine contractions and functional tests. Normally, at least 2 accelerations of heart rate should occur in 10 minutes.
• Deceleration (slowing the heart rate)- this parameter is taken into account in the same way as accelerations. On the graph these are the teeth looking down.

The duration of decelerations may vary:

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

In addition, in conclusion there is always such a thing as signal loss. This happens when the sensors temporarily lose the sound of your 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 ranging from 0 to 5 points.

The printout, which is handed to the pregnant woman, contains the following 8 parameters:

• Analysis time/signal loss.
• Basal heart rate.
• Accelerations.
• Decelerations.
• Variability.
• Sinusoidal rhythm/amplitude and oscillation frequency.
• Frequency of movements.

With an absolute norm, 8 out of 8 parameters must be met. 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, it is impossible to do without repeating CTG. The cardiotocogram displays the heart rate range (two numbers are indicated).

During recording, a graph of two types of signal is displayed on the calibration tape

Evaluation points

In the process of developing cardiotocography, experts identified objective criteria for assessing recordings and compiled many tables. To interpret the results of CTG, several scales are used. Most often they resort to the Fisher scale (10 points) or Krebs scale (12 points). In conclusion, a double result may be indicated - a fischer and a krebs score.

Fisher criteria

The scoring chart, developed by an American obstetrician-gynecologist, presents a number of criteria that are scored from 0 to 2 points. The final score is determined by summing all grades. According to Fisher, specialists conduct “manual” calculations, focusing on what they see on the calibration tape.

Having assessed the criteria, there are 3 main conditions of the fetus:

• Normal indicators are 8–10 points. The baby's heart is beating well and he is moderately mobile, and there is absolutely no suspicion of oxygen starvation.
• Condition that raises doubts - 5–7 points. This result may indicate the initial stage of oxygen starvation and requires special monitoring of the pregnant woman.
• Poor fetal condition - 0–4 points. This indicates severe hypoxia. If urgent measures are not taken, the baby may die 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. If the CTG record had a score of 8 or more points, then when labor begins, the procedure is repeated after 2-3 hours, and in earlier stages the pregnant woman is released for 3-7 days before a repeat 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 given, from 1 to 4 motor reactions are scored 1 point, if there are 5 or more reactions in 30 seconds, then 2 are given points.

In view of this criterion, the Krebs scale has a 12-point rating system. If the result on this scale was from 9 to 12 points, 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 the CTG report contains 11 points, then there is no doubt that the Krebs scale was used when decoding. If the score is 9 points, then the result is considered good in any case. But if there was no note that the assessment was carried out according to Fisher, then you should still consult with a specialist.

Dawes-Redman tests

These criteria are developed for automatic devices. The computer evaluates the recording 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 summarized and a special variability indicator is displayed - STV. This sensitive parameter can detect signs of fetal distress and predict adverse pregnancy outcomes.

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

• normal indicators indicating a healthy pregnancy - STV 6–9 ms;
• borderline 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 coming hours may result in intrauterine death - STV less than 2.6 ms.

This assessment system is not practiced during labor, but is successfully used for monitoring during pregnancy. Typically, 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 bad and questionable CTG results can serve as a serious reason for an emergency cesarean section.

The leading obstetrician-gynecologist evaluates the results

Fetal health indicators

Having assessed the CTG indicators, doctors determine the value of the PSP (an indicator of the condition of the fetus). There are 4 standard conclusions on PSP. Below 1.0 are normal indicators (sometimes starting from 1.05). At the same time, if borderline values ​​of 0.8-1.0 were obtained, 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 CTG recording within a week. From 2.01 to 3.0 - severe deviations. In this case, the woman is recommended to go to hospital to take measures to maintain the pregnancy. PSP of 3.0 or more is a critical condition of the fetus. The pregnant woman should be urgently hospitalized, and emergency delivery will most likely be indicated.

CTG is normally no different from 33 weeks to 36 weeks and is characterized by the following signs: 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 slowdown in rhythm.

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

• Moderate amplitude of heart rate decelerations: basal rhythm - 160–180 beats/min, range of variability - more than 25 beats/min, early rhythm decelerations - less than 30 beats/min, late - less than 10 beats/min, pronounced accelerations of the heart rate. With such indicators, childbirth should proceed naturally without the intervention of obstetricians.
• The condition is on the verge of risk: the main CTG line is from 180 beats per minute, the variability of the curve is less than 5 beats/min, early decelerations of the rhythm are 30–60 beats/min, late ones are 10–30 beats/min. In this case, natural delivery is not excluded, but the Zadinga test is additionally performed. After this, the obstetricians take all the necessary manipulations to achieve a natural birth, 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 decelerations of heart rate exceed 60 beats/min, late decelerations exceed 30 beats/min. The actions of obstetricians in this case do not differ from those carried out in case of risky conditions of the fetus.
• Critical condition 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 cannot tolerate delay; a caesarean section must be performed urgently.

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

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

Pathological CTG

There are 3 pathological variants of CTG.

Silent or monotonous CTG

It is characterized by the absence of accelerations and decelerations, but the basal heart rate is within normal limits. The graphical representation of such cardiotocography is close to a straight line.

Sinusoidal CTG

The graphical representation of such cardiotocography has the form of a sinusoid. This CTG indicates severe oxygen starvation of the fetus. Sometimes it is detected when a pregnant woman is taking psychotropics or drugs.

Lambda rhythm

It is characterized by rapid alternation of acceleration and deceleration. In most cases, this CTG pathology 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, there are conditionally pathological types of CTG with characteristic signs: the presence of decelerations immediately following accelerations, passivity of fetal movements, insufficient range and rhythm variability.

If questionable results are obtained with standard CTG, a recording is made with functional tests:

• Non-stress test. Heart rate studies are carried out against the background of natural fetal movements. Normally, 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. The pregnant woman is given oxytocin and the baby's heart rate changes are monitored. Normally, accelerations should be observed, the basal rhythm should be within the acceptable range, and decelerations should be absent. If, after the administration of this drug, the fetus does not experience an acceleration of the rhythm, but rather it can be noted that the heart contractions are slowing down, then this indicates oxygen starvation.
• Mammary test. This test produces natural oxytocin in a woman's body by massaging her nipples for 2 minutes. Next, an assessment is made, as in the case of the administration of synthetic oxytocin.
• Exercise test. A CTG recording is made immediately after the pregnant woman performs a series of activities that involve physical activity. Most often she is asked to climb stairs up to 2 flights of stairs. In response to such actions, the fetal heart rate should increase.
• Breath test. During the CTG recording, a pregnant woman should hold her breath first while inhaling and then while exhaling. 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 baby'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 used. Such a study helps to choose the right tactics for labor management, taking into account how the fetus tolerates the emerging loads.

Fetal cardiotocography (CTG) helps monitor the condition of the child in the womb and monitor its normal development. The study is part of a set of mandatory procedures (ultrasound and Doppler), thanks to which it is possible to determine pathological processes in the early stages of development (hypoxia, abnormalities in cardiac activity).

Cardiotocography helps to determine the condition of the fetus

Fetal cardiotocography - what is it?

Fetal CTG is the most accurate study that allows you to give a comprehensive assessment of the condition of the unborn child:

• assess cardiac activity and heart rhythm;
• determine the baby’s motor activity;
• study the frequency of uterine contractions and evaluate the child’s reaction to such movements of the reproductive organ.

The essence of cardiotocography is that 2 sensors are attached to the mother’s abdomen, each of which performs its own function:

• one electrode reads the fetal heartbeat (attached in the place where the rhythm can be heard best);
• another sensor records uterine contractions (located in the lower abdomen - the fundus of the uterus).

During the examination, information is transferred to a special apparatus, which generates a graph of values. The obtained indicators are compared with normal parameters, on the basis of which a decoding and conclusion is made.

What the sensors look like together with the reading device is shown in the photo. The coefficient of technical readiness of the equipment is also indicated here.

CTG shows the condition of the placenta

What week is CTG performed?

Fetal heart rate can be monitored using cardiotocography at 28 weeks. At this time, contractions are already clearly visible, but it is not yet possible to assess the activity of the cardiovascular system as a whole. To get a complete picture of the condition of the fetus, CTG is recommended to be done from 30 weeks.

Starting from the last trimester, it is already possible to study not only the level of contractions of the vital organ, but also examine a number of indicators:

• the child’s reaction to the frequency of uterine contractions;
• the nature of the heartbeat during the movement of the fetus itself;
• the baby's activity cycle and sleep or rest state.

CTG can be performed from 28 weeks of pregnancy

CTG may be prescribed earlier than 30 weeks in cases where there are suspicions of negative deviations in the normal embroidery of the fetus. Depending on the identified pathologies, the procedure can be done with a frequency of 2 times a month to 1 time every 5 days. If the pregnancy is progressing normally, 2-3 procedures are sufficient for the entire third trimester.

Preparing pregnant women for cardiotocography

Fetal examination using CTG is carried out while the baby is awake in the womb. Therefore, it is important to make sure that the child is not sleeping before the procedure, otherwise the indicators will be distorted. For the examination to go well and give reliable results, a pregnant woman needs to follow a few simple rules.

1. Do not conduct the examination on an empty stomach. It is recommended not only to eat well, but also to eat something sweet. The entry of glucose into the blood will stimulate the fetus.
2. Do light physical exercises - walk up the stairs, take a walk in the fresh air, do simple exercises with a fitball.
3. Do a breathing exercise. Take deep breaths and exhales. Kids react positively to such manipulations. But don’t hold your breath - a lack of oxygen can cause stress in the baby and harm him.

Before the cardiotocography procedure, do breathing exercises

When preparing for the procedure, it is necessary to remember that the awakening of the fetus should be natural. It is forbidden to knock on the stomach, wipe it with cold water or apply cold objects. Otherwise, this will cause stress in the small organism, which will greatly distort the analysis results.

How is CTG done?

The examination is painless and safe for mother and child. A pregnant woman needs to take a pillow or blanket with her to sit comfortably on the couch. After the patient has taken a position, lying or reclining on her back, the abdomen is exposed and 2 electrodes are applied - 1 in the place of greatest audibility of the child’s heart rhythm, 2 in the lower abdomen (fundus of the uterus).

Interpretation of examination results

Decoding CTG involves the interpretation of quantitative and qualitative indicators of the baby’s intrauterine development.

Table “Description of the main parameters of CTG”

Cardiotocography recording lasts from 35 to 60 minutes. During prolonged examination, signal loss may be observed. This indicator is not a prerequisite in CTG. If the frequency of signal loss has increased, but the overall picture is without deviations, everything is in order.

During a normal pregnancy, experts use the Dawes-Rodman criteria:

• heart rate amplitude within 5-26 beats per minute;
• there are fetal movements (at least 1-2);
• SVT – from 3 milliseconds;
• registration of at least 2 accelerations in 10 minutes;
• no decrease in heart rate.

If all criteria are met within 10 minutes, the fetal condition is considered normal and the study can be completed. If the values ​​are not observed within the allotted time, the figo CTG is considered suspicious, and all study indicators are carefully checked.

Fisher scale

The interpretation of CTG results includes not only a description of each parameter, but also their assessment. For this purpose, it is customary to use the 10-point Fisher scale. All components of the test are scored from 0 to 2, after which the values ​​are summed up and the specialist can select an indicator of the fetal condition (FSP).

1. From 8 to 10 points – good KTG during pregnancy. The baby feels great, pregnancy is proceeding normally. A repeat study can be done closer to childbirth.
2. From 6 to 7 – initial disruption in supplying sufficient oxygen to the fetus.
3. From 1 to 5 – bad CTG. Dangerous condition of the child in the womb.

CTG interpretation table using the Fisher method

The lower the total score, the higher the risk of premature birth, since there is a greater likelihood of hypoxia, intrauterine infections, anemia or abnormalities of the cardiovascular system. This requires additional examination (ultrasound, Doppler, laboratory tests) and the appointment of appropriate therapy.

Fetal reactivity index

An important indicator of the condition of the baby in the womb. It determines the level of reactivity of the incorrect system to external stimuli.

The index is assessed on a 5-point scale:

• normal reactivity of the nervous system is reflected by the highest score – 5;
• initial negative violations – 4 points;
• moderate development of pathological abnormalities – 3 points;
• pronounced disturbances in reactivity – 2 points;
• severe degree of pathology in the reactivity of the incorrect system – 1 point;
• The baby’s complete lack of reaction to external stimuli – 0 points.

Indicators of fetal reactivity

Non-stress test

Monitoring and evaluation of cardiac activity is carried out using a non-stress test. A good value for such an indicator is when it is negative. In this case, 2–3 accelerations should be present. In case of a positive result or its absence, we are talking about oxygen starvation of the fetus. This may also be a false alarm, so the doctor recommends a repeat test.

Fetal non-stress test to assess cardiac parameters

Harm of cardiotocography

Cardiotocography is one of the few studies that is absolutely safe for the health of the baby and mother. It will not cause harm even with high frequency of repetitions. Depending on the detected abnormalities, CTG can be performed on a daily basis if the patient's condition requires it. In addition, cardiotocography is a mandatory measure immediately before childbirth and during labor and contractions. Its use here does not depend on the course of pregnancy (normal or with pathologies), but helps to monitor the condition of the baby while passing through the birth canal.

Cardiotocography is an absolutely safe procedure

It is important for pregnant women to understand that CTG is not only the most effective method of monitoring the condition of the fetus, but also completely safe. There is nothing to worry about.

The most accurate method for studying the development of a baby in the womb is cardiotocography. The method is highly informative – it assesses the state of the baby’s cardiac activity, nervous system and activity. With its help, you can identify pathological changes in a small organism and eliminate them in time. The examination is completely safe and does not harm the health of the mother and baby.

Pregnancy is an important stage in the life of every woman, which changes her both inside and out. During the period of the birth of a new life, the expectant mother often listens sensitively to any changes in her body. And this is not surprising, because at this time the body of a woman and child is most susceptible to various negative influences of the external environment.

One of the methods for assessing the condition of the fetus is cardiotocography. It is carried out to exclude or timely identify pathological conditions of the mother and child that pose a threat to the course of pregnancy or to the future health of the newborn baby. In this article we will talk about decoding CTG at the 32nd week of pregnancy in normal and pathological conditions.

Indications for the procedure at 32 weeks

Cardiotocography makes it possible to identify disorders such as polyhydramnios and oligohydramnios, fetal hypoxia, intrauterine infection, abnormalities in the structure of the heart and blood vessels, and fetoplacental insufficiency.

The procedure is prescribed in the following cases:

• The presence of endocrine or systemic diseases in the mother (diabetes mellitus, anemia of various origins, etc.).
• Conditions that threaten the course of pregnancy (malpresentation of the baby, multiple and post-term pregnancy, severe toxicosis, persistent increase in body temperature, etc.).
• Previously identified abnormalities during ultrasound diagnostics (deviation of the fetal size from the norm, decrease in its motor activity, developmental delay, pathology in the amniotic fluid and placental circulatory system).
• Previously recorded cases of premature birth and spontaneous termination of pregnancy in the early stages.
• Rhesus conflict between mother and fetus.

This type of diagnosis does not require special preparatory measures. In order for the results to be most accurate, the expectant mother should lie as still as possible, so before the study it is better to go to the toilet in advance. It is prohibited to take analgesics or sedatives 11–12 hours before the start of CTG.

It is allowed to carry out the procedure in a position on your side or half-sitting, resting your back on a previously prepared pillow. A special device consisting of two parts is attached to the expectant mother’s belly. The first sensor is lubricated with gel and installed in the projection of the best audibility of the fetal heartbeat.

The second - to the area of ​​the fundus of the uterus to record its excitation and further contractions. Next, the pregnant woman is offered a special button that she will press during periods when the baby moves. The appointment is made by a doctor within 30–60 minutes. A special device records all data in the form of graphs on paper tape.

Correct placement of sensors during CTG reduces errors in the study

Basic indicators of cardiotocography

The fetal CTG norm is a series of digital values ​​that are examined by the doctor to confirm the normal or pathological intrauterine development of the child. During the study, the following indicators are recorded.

Basal rhythm (BHR)

To calculate this value, heart rate indicators are recorded every second, after which significant increases and decreases in the rhythm are subtracted and the average value is obtained over a time period of 10 minutes. Normally, at 32 weeks of pregnancy, the heart rate during active movements of the child is 130–180 beats, and during sleep 120–160.

If the values ​​of the basal rhythm are within the normal range, this indicates the absence of fetal hypoxia. A heart rate higher or lower than the given indicators indicates that the baby’s body is not receiving enough oxygen, and this can have a detrimental effect on the nervous system and the overall development of the child.

Basal rate variability

Amplitude is considered to be vertical fluctuations from the main line of the heart rate, frequency is the spread of indicators per minute. Normally, the baby's heart rate in the womb should not be the same all the time. Normal cardiotocography is indicated by such concepts as undulating or saltatory rhythm, when the spread is 10–15 beats per minute, and the amplitude is 25–30 beats per minute.

A monotonous rhythm is characterized by fluctuations in heart rate from 0 to 5 beats per minute. Slightly undulating – amplitude from 5 to 10 beats/min. Both of these options indicate pathology.

CTG helps to identify fetal hypoxia and other life-threatening conditions

Acceleration

This indicator is displayed on the graph in the form of teeth, the tops of which are directed upward. They reflect the acceleration of the heart rate. Normally, this should occur during uterine spasms, during active fetal movements, and in response to stress tests. 2-3 increases are allowed over 15 minutes.

Deceleration

The appearance of teeth on the graph, the tops of which are lowered down. This indicator reflects a decrease in heart rate. Normally, they should not be present or be mild in depth, frequency and duration. The following types of decelerations are distinguished:

• Early - occur simultaneously with the contraction, begin and end gradually. The appearance of such an indicator may be a sign of compression of the umbilical cord.
• Late - occur in response to uterine contractions, but are delayed by 0.5 minutes or more, and their peak is recorded after the maximum tension of the organ walls.
• Variable - there is no connection between the slowing of the rhythm and the occurrence of contractions. The graph displays spikes of varying shapes and durations. Such deviations from the norm occur when the umbilical cord is compressed or there is insufficient amniotic fluid.

Number of uterine contractions

Periodic spasms of the muscular membrane of this organ are a completely physiological process. The norm for 32 weeks is considered to be the duration of such contractions no more than 30 seconds, and the ratio with the basal heart rate is no higher than 15 percent.

Normal cardiotocography results

Fisher's ten-point scale

Doctors use this scale to evaluate CTG results. The essence of the procedure is that each indicator is awarded from 0 to 2 points. All values ​​are added up and determine the information content of this diagnostic method, as well as the presence or absence of pathologies.

• 1-5 points – the condition of the fetus in the uterus is poor, it experiences a pronounced lack of oxygen.
• 6-7 points – mild hypoxia, borderline state.
• 8-10 points – the child’s body does not experience oxygen starvation and is in excellent condition.

Fetal health indicator (FSI)

This value is calculated automatically. The following PSP options are distinguished:

• Less than 1 is normal. However, if the CTG value is from 0.8 to 1.0 during pregnancy, it is recommended to repeat it.
• From 1 to 2 – initial changes in the general condition of the fetus. Outpatient treatment and control cardiotocography after one week are recommended.
• From 2 to 3 – the child’s condition is serious. Urgent hospitalization and immediate initiation of treatment are required.
• More than 3 – the condition is extremely serious. The question of emergency management of childbirth is raised.

Fetal reactivity index and non-stress test

The first indicator reflects the state of the fetal nervous system in response to external influences. Such stressful situations primarily affect the state of the cardiovascular system. Points are used for calculation, where:

• 0 – complete absence of response to external stimulus.
• 1 – pronounced decrease in reactivity.
• 2 – noticeable decrease in reactivity.
• 3 – moderately expressed response to external influence.
• 4 – initial degree of pathological reactivity.
• 5 – adequate response to external influences.

Applying a warm or cold object to the pregnant woman's abdomen is used to assess fetal reactivity

A non-stress test is carried out to assess the state of the baby’s cardiovascular system during his voluntary movements. Normally, such a test should be negative, which implies the presence of 2 or 3 increases in heart rate by 15 beats, lasting no more than 20 seconds.

Despite the large number of indicators, cardiotocography is only an additional diagnostic method. For a comprehensive assessment of the condition of the mother and fetus, other instrumental examinations, laboratory test data and consultation with an experienced specialist are necessary.