CTG during pregnancy transcript 35 week. What is cardiotocography (CTG) during pregnancy, and how is it done? Indications for cardiotocography

It is not possible to determine the condition of the child in the womb by external characteristics. If you control only movement, you may not notice the serious and dangerous signs that occur when the fetus is suffering. Cardiotocography (CTG) during pregnancy shows that the child has problems or developmental abnormalities that need to be dealt with immediately.

What is CTG and what is it for?

Cardiotocography is a serious fundamental component of comprehensive monitoring of the vital functions of the fetus.

Uterine contractions and heart rate are recorded using special sensors. They recognize the signal reflected from the baby's heart. The results are displayed on the monitor screen, and the doctor calculates the number of beats per minute.

CTG is very similar to, but only determines the fetal heart rate.

During the procedure, the intervals between peaks are recorded. The data is recorded on a special tape in the form of a curve graph. The results of the procedure are similar to a cardiogram.

The second line on the CTG monitor records the intervals of uterine contractions.

Combining the image of two lines over time helps to study the work of the baby’s heart and the frequency of uterine contractions.

Before starting the examination, the doctor determines the zone of best audibility of the fetal heartbeat along the front wall, and then fixes the device’s sensors in this place.

When and how often is the examination done?

In the normal course of pregnancy, this procedure is carried out once. If a developmental pathology is suspected, the study is ordered again. If an intrauterine disease is detected, CTG is performed systematically to monitor changes in the functioning of the small heart.

CTG during pregnancy is prescribed no earlier than the 26th week, because before this period, cardiac pathologies in the baby do not appear.

By week 33, the baby begins to alternate between periods of calm and activity. A connection is established between heart function and mobility. Using cardiotocography, you can determine the condition of the heart in both periods.

Fetal CTG is also performed during natural childbirth and surgery. This is necessary and important in order to find out the general well-being of the fetus and make the right decision about the subsequent management of the birth.

Special observation is mandatory for babies whose final examination reveals entanglement in the umbilical cord.

Indications for the study

The need for CTG is needed in the following cases:

Heart rhythm pathology during initial cardiotocography.
Unfavorable course of the previous pregnancy (miscarriage, prematurity, identified pathologies of fetal development, congenital defects in older children).
Cases when a pregnant woman feels atypical behavior of the fetus (frequent movements, anxiety or apathy of the baby).
Maternal diseases (chronic, infectious and others).
The period after intrauterine treatment of the fetus.
, causing a lack of oxygen, which leads to the baby.
Chronic infections and harmful habits of the mother.
Post-term pregnancy.

There are two diagnostic methods: external and internal.

The first of them is used after 30 weeks during obstetrics. The devices are applied to the abdominal area, and the woman is positioned on her back or left side. The first sensor records the heart rate. The second is the frequency of uterine contractions.

By the time of birth, babies assume the head position. After palpation by the obstetrician, the area of the mother’s abdomen adjacent to the baby’s back is palpated. It is in this place that the first sensor is attached.

If a woman is expecting twins, a CTG is recorded separately for each child.

The favorable time of day for the procedure is before lunch from 9 to 14 and before bedtime from 19 to 24. During this period, fetal activity is at its maximum.

The second sensor reflects the activity of the uterus and is located on the right uterine base.

The doctor hands the sensor into the patient’s hands, and it is used to record fetal movements. When you press the remote control button, a certain mark appears in the tape.

An internal procedure using a spiral electrode is performed during labor.

Contractions are determined in this way. A device is attached through the vagina to the baby's head.

Mandatory indications for the internal method are cervical dilatation by 2 cm and water breaking.

This method is not very common, unlike the external one.

Preparation for the procedure

CTG should not be performed on an empty stomach, after a heavy lunch, or within two hours after eating food. The baby's body depends on the condition of the body and the health of the mother.

After eating, blood sugar increases, which affects excessive mobility and activity. The picture of the study may turn out to be blurry and the doctor may make an incorrect diagnosis.

There are situations when a healthy mother shows abnormal changes in the child’s body on a CTG recording.

This is due to the following factors:

Eat a large meal before CTG.
The recording was carried out while the child was sleeping.
pregnant.
Excessive fetal activity.
Insufficient sensor fit.
Multiple pregnancy.

Before a long and monotonous procedure, you need to rest and get a good night's sleep. It is allowed to eat a small piece of chocolate to keep the baby awake.

Since CTG is a rather lengthy procedure, it is recommended to go to the toilet before it.

How long does CTG last?

The duration depends on mobility and is up to 40 minutes. The results of the procedure are explained within 20 minutes.

At least 2 episodes of movement lasting 20 seconds or more, as well as the number of uterine contractions during this period, are recorded.

CTG indicators

Cardiotocographic tapes are interpreted in different ways. To obtain a regular assessment, the rules established by the FIGO committee are followed.

Indicators are divided into three types: normal, suspicious and abnormal.

Suspicious CTG according to figo requires additional stress examination. Its typical manifestations are: basal rhythm, characterized by a heartbeat of 100-110 and 150-170 beats/min.

Normally they reach 5-10. If acceleration is not noted (increase, increase in heart rate).

All characteristics are assigned 0-2 points. At the final stage, the numbers are summed up and a conclusion is drawn about the state of health. For example, a CTG score of 8 means that the pregnancy is proceeding without any peculiarities, complications or pathologies.

A monotonous rhythm occurs when there is a lack of oxygen or when the child sleeps for a long time. Sinus rhythm is a recording in which the heart beats faster.

If the child is calm and the sinus rhythm is fixed, this indicates a complex course.

Decoding the results

The CTG results are deciphered by the doctor after receiving the examination results. When deciphering indicators, several factors are taken into account:

basal rhythm (HR) and its variability;
slowing or speeding up heart rate;
uterine activity (tocogram).

The results of the study are assessed on a 10-point scale, where:

9 -12 points - the baby’s heart function is normal;
6 - 8 points indicates oxygen starvation of the fetus. After completion of treatment, a repeat procedure is required;
5 points or less - severe hypoxia of the child. In such cases are shown.

Detailed explanation of the CTG table:

The highest indicators are a calm course of pregnancy, not complicated by gestosis and other pathological conditions of the woman’s body. The norm for CTG during pregnancy is 8-10 points.
From 6-7 - primary signs of deterioration and suffering, hypoxia. Prescribed prior to examination.
5 or less - hospital treatment and qualified assistance are required. There is a risk of threat to life.

The graph shows that upturns turn into downturns. The doctor estimates the average value. Mommy can personally evaluate the CTG schedule. At arm's length, move the information sheet aside and draw a straight line along the cardiotocogram.

Doctors are also studying the reduction of heart rate. This is a graph with small teeth that characterize the deviation from the basal rhythm.

There should be six of them per minute and no more. This is a typical occurrence at 32-39 weeks. The doctor is alert if the change in the size of the teeth is 0-10 beats/min.

Deceleration is a delay and deterioration in heart rhythm (looks like depressions on the graph). Normally, they are not noted or are insignificant.

If the level is exceeded 25 beats/min, this interpretation of CTG during pregnancy suggests that there is a lack of oxygen or umbilical entanglement.

When changing the number of teeth, pay attention from 32-38 weeks. When a baby kicks, his heart beats faster for a couple of seconds. The cardiogram shows a large tooth growing upward—increasing frequency.

If there are at least 2 of them in 10 minutes, the dynamics are positive. Reduction or curtailment is the opposite phenomenon. These are teeth located with the tip down from 34-39 weeks.

The effect of the procedure on the fetus

Thanks to CTG, they learn about the child’s vital activity and the progress of the birth process, identify anomalies and begin to eliminate them.

The procedure is completely harmless to the child, so the study can be carried out an unlimited number of times.

Video: CTG during pregnancy

Cardiotocography refers to methods for prenatal diagnosis of the condition of the fetus and is widely used due to the simplicity of the study, safety for mother and child, informativeness and stability of the information provided.

CTG records the fetal heart rate, both at rest and in motion, in response to uterine contractions and exposure to various environmental factors. In addition to the fetal heart rate (HR), uterine contractions are also recorded during CTG. The method is based on the Doppler principle, and the fetal heart rate is captured by an ultrasonic sensor. The sensor that records uterine contractions is called strain gauge.

The need for CTG

According to the order of the Ministry of Health of the Russian Federation No. 572 dated November 1, 2012, CTG should be performed on a pregnant woman (with physiological pregnancy) at least 3 times in the third trimester, and always during childbirth.

CTG is performed

in order to determine the fetal heart rate and the frequency of uterine contractions,
assessing the condition of the fetus both before birth and during the birth process (during contractions and between contractions),
identifying fetal distress and resolving delivery issues.

Additional indications for CTG are:

complicated obstetric history;
woman's anemia;
Rhesus conflict pregnancy;
post-maturity;
a lot of water and little water;
threat of premature birth;
assessment of the effectiveness of treatment of fetoplacental insufficiency and fetal hypoxia;
control after unsatisfactory CTG results;
multiple births;
delayed fetal development;
severe extragenital pathology of the mother.

Dates

Cardiotocography is indicated from 32 weeks of gestation. It is also possible to conduct CTG earlier, from 28 weeks, and in shorter periods of pregnancy CTG is not performed at all due to the impossibility of correct interpretation of the results. The indicated pregnancy periods for CTG are based on the fact that only by the 28th week does the fetal heart begin to be regulated by the autonomic nervous system, and its heart rate responds to the movements it makes. In addition, by the 32nd week of gestation, the cyclicity of sleep and wakefulness of the unborn child is formed.

If the pregnancy proceeds without complications, then CTG is performed once every 10 days; in case of complications, but “good” results of previous CTG, the study is repeated after 5-7 days. In the case of intrauterine hypoxia, daily or every other day CTG is indicated (either until the fetal condition normalizes, or until the issue of the need for delivery is decided).

During labor (without deviations from the norm), CTG is performed every 3 hours. In case of complications - more often, as determined by the doctor. It is advisable to conduct the period of contractions under the constant monitoring of CTG.

Preparing for CTG

No special preparation is required for the study. You should familiarize the woman with some rules in advance:

the procedure is absolutely safe for the fetus and painless;
the study is not carried out on an empty stomach and immediately after eating, only after 1.5-2 hours;
before CTG you should visit the toilet (the study takes from 20 to 40 minutes);
in case of smoking, the patient should abstain from cigarettes for 2 hours before CTG;
during CTG, the patient should not move or change body position;
obtain written consent to conduct CTG from the woman.

Methods

CTG can be indirect (external) and direct (internal).

The examination is carried out with the woman either on her left side or half-sitting (to prevent compression syndrome of the inferior vena cava). The ultrasound sensor (which records the fetal heart rate) is treated with a special gel to ensure maximum contact with the pregnant woman's skin. The sensor is placed on the anterior abdominal wall in the area of maximum audibility of fetal heartbeats. A strain gauge sensor that records uterine contractions is placed in the area of the right corner of the uterus (it is not lubricated with gel).

The patient is given a special device in her hand, with which she independently notes the baby’s movements. The procedure takes 20-40 minutes, which is due to the frequency of periods of sleep (usually no more than 30 minutes) and wakefulness of the fetus. Registration of the basal rhythm of the fetal heart rate is carried out for at least 20 minutes until 2 movements are recorded lasting at least 15 seconds and causing an acceleration of the heart rate by 15 heartbeats per minute.

Internal cardiotocography is performed only during childbirth and under certain conditions:

opened amniotic sac and discharge of water;
the opening of the uterine pharynx is at least 2 cm.

To conduct direct CTG, a special spiral electrode is applied to the skin of the presenting part of the fetus, and uterine contractions are recorded either by inserting an intra-amnial catheter or through the anterior abdominal wall. This study is considered invasive and is not widely used in obstetrics.

When conducting non-stress cardiotocography, the fetal heartbeat is recorded in natural conditions, taking into account fetal movements. If unsatisfactory results of non-stress CTG are obtained, tests (functional tests) are used, which is called stress CTG. These tests include: oxytocin, mammary, acoustic, atropine and others.

Decoding CTG

When analyzing the resulting fetal cardiotocogram, the following indicators are assessed:

basal rhythm of the fetal heart rate, that is, the average heart rate between instantaneous heart rate readings either in the interval between contractions or over a 10-minute period;
basal changes are fluctuations in fetal heart rate that occur regardless of uterine contractions;
periodic changes are changes in fetal heart rate that occur in response to uterine contractions;
amplitude is the difference in heart rate values between the basal rhythm and basal and periodic changes;
recovery time - the period of time following the end of uterine contraction and the return to the basal heart rate rhythm;
acceleration or increase in heart rate by 15-25 per minute in relation to the basal rhythm (a favorable sign, confirms the satisfactory condition of the fetus, occurs in response to movement, tests, contractions);
deceleration - a decrease in heart rate by 30 or more and lasting at least 30 seconds.

Indicators of a normal antenatal cardiotocogram:

the basal rhythm is 120-160 per minute;
amplitude of rhythm variability within 10-25 per minute;
there are no decelerations;
registration of 2 or more accelerations within 10 minutes of recording.

Questionable cardiotocogram:

the basal rate is either 100-120 or 160-180 per minute;
the amplitude of rhythm variability is less than 10 per minute or more than 25;
there are no accelerations;
registration of shallow and short decelerations.

Pathological cardiotocogram:

basal rate is either less than 100 per minute or more than 180;
the amplitude of rhythm variability is less than 5 per minute (monotonic rhythm);
registration of pronounced variable (having different forms) decelerations;
registration of late decelerations (occurring 30 seconds after the onset of uterine contractions);
sinusoidal rhythm.

Interpretation of CTG points

To assess the condition of the fetus, the Savelyeva scale is used.

Table: interpretation of CTG scores

CTG parameters
Basal rhythm HR/min)		more than 180 or less than 100
Basal rate variability	number of heart rate changes/min
Basal rate variability	change in heart rate	5 or sine wave type	5-9 or more than 25
Accelerations (per min)		None	Periodic	Sporadic
Decelerations (per min)		Late long, variable	Late short-term, variable	Absent, early

8-10 points indicates no problems
6-7 points - initial signs of hypoxia (inpatient observation is recommended, treatment is prescribed)
less than 5 - hypoxia occurs, i.e. oxygen deprivation (prompt hospitalization required)

Some studies during pregnancy

After 7 months of pregnancy, the expectant mother can receive a referral for CTG. This study in the last trimester is considered one of the most informative. However, it is precisely this that raises the most questions among pregnant women, since it is completely unclear how and what is being examined and how to understand what is written in the conclusion. In this article we will talk about CTG in more detail, and also help you decipher its results.

What it is?

Behind the abbreviation CTG lies a study called cardiotocography. At its core, it is a constant, continuous recording of the baby’s heartbeats, uterine contractions, as well as the child’s motor activity. All these parameters are recorded synchronously and immediately recorded in real time by a recorder or computer program on a calibration tape.

The rhythm of a beating baby's heart is captured by an ultrasonic sensor, and uterine contractions are detected by a strain gauge sensor.

The first graph is called a tachogram, and the second is a histogram. Due to its simplicity, safety and information content, CTG is today the most popular way to obtain information about the child’s condition, who has very little left before birth - a couple of months.

CTG is prescribed to all pregnant women who are registered at the antenatal clinic. In an uncomplicated, normal pregnancy, the first examination is carried out between 30 and 32 weeks, then a similar examination is carried out immediately before birth in a maternity hospital during a planned hospitalization. If the baby’s condition raises questions, then CTG can be performed earlier, starting from 28-29 weeks. In case of serious complications of pregnancy, examination may be carried out daily.

CTG is also used in the birth process itself. An examination during pregnancy, when sensors are placed on the expectant mother’s belly, is called external or indirect CTG. Direct cardiotocography is carried out when the integrity of the fetal membrane is broken, the waters have broken, and a thin electrode sensor is inserted directly into the uterus.

What does it show?

CTG allows you to find out how the child is feeling. First of all, the device records and displays heart rate (heart rate) - the main parameter that allows you to judge the baby’s well-being. An ultrasonic sensor, based on the Doppler effect, sends out an ultrasonic wave. It is reflected from tissues and moving blood cells in blood vessels and sent back to the sensor. As a result it becomes obvious at what frequency the small heart beats.

The tone of the uterus and fetal movements are measured by a strain gauge, which is a wide belt encircling the belly of the expectant mother.

If the uterus contracts or tenses, if the baby makes a revolution or stretches, the abdomen will slightly change in volume, which will not escape the sensitive sensor and will immediately be reflected in the graph.

The study also has its own nuances, which are very important for correct diagnosis. So, what matters is not only the frequency with which the baby’s heart beats, but also how this rhythm changes depending on activity, movements and other factors. Therefore, rhythm variability, the myocardial reflex (the heart beats faster when moving), as well as any other periodic changes in the child’s heart function are assessed.

Indications for examination

Like any other test or procedure, CTG during pregnancy is only a recommended technique; the Ministry of Health strongly advises pregnant women not to refuse it. But the final word, in any case, remains with the expectant mother - if she does not want to go for this diagnosis, no one can force her.

Doctors try to do research on all pregnant women. But the procedure is especially indicated for certain categories of expectant mothers:

Any pathology of pregnancy. This includes gestosis, oligohydramnios and polyhydramnios, the threat of premature birth, infectious and non-infectious diseases that the expectant mother suffered during the period of bearing the baby, chronic ailments that she has, high or low blood pressure in a woman, etc.
Strange behavior of the child. If the baby suddenly begins to move rarely and sluggishly or, conversely, his motor activity increases.
The appearance of abdominal pain in the mother. Any pain syndrome, of any nature and strength, necessarily requires a CTG.

Complicated obstetric history. You should monitor your baby using cardiotocography more often if a woman’s previous pregnancies resulted in premature birth, the death of a child in utero, or the birth of a child with severe developmental pathologies.
Difficult previous labor or caesarean section. If such facts occurred in the past, then the next late pregnancy will definitely need frequent monitoring, including with the help of CTG.

Women from the designated risk group may be diagnosed several times during pregnancy. The frequency is determined by a doctor who knows well the characteristics of pregnancy in a particular woman.

How is it carried out?

This simple examination can be done at the antenatal clinic at your place of residence, as well as at any private clinic that offers pregnancy planning and management services. The procedure is completely painless and does not cause any discomfort.

At the doctor's office, the woman will be asked to make herself more comfortable. She can lie down, sit down or sit in a semi-sitting position, the main thing is that she is comfortable, since CTG lasts quite a long time - from half an hour to an hour, and in some cases longer if the examination is incorrect or its results are abnormal or questionable.

A wide special belt is put on the expectant mother's stomach - the same strain gauge sensor, and a small ultrasonic sensor of a round or rectangular shape is attached under it. They try to position the ultrasound sensor so that it is as close as possible to the baby’s heart. As soon as the doctor hears a distinct rhythm, he will fasten the belt, fix the sensors and start the computer program, which will begin to record the indicators and draw graphs. If the examination is carried out on an old device, the recorder will draw.

The movements will be captured by a strain gauge belt. If the diagnosis is carried out using a device, then the woman will have a button in her hand, which she will be asked to press every time as soon as she feels a distinct movement of her baby. The decision to stop measurements is made by the program itself; as soon as the amount of information necessary to calculate the results is received, the “session” will end and the result will be printed.

Preparing for a CTG test is quite simple. It is advisable to have a good rest and sleep the day before, so as not to get distorted, unreliable results. You should not go for the study on an empty stomach; it is best to eat before leaving, and go to the toilet before going to the doctor’s office, because you will have to sit in one position for a long time. It is worth walking along the way to “cheer up” the baby, because a sleeping fetus will not be able to demonstrate the necessary motor activity.

According to reviews from expectant mothers, eating a small chocolate bar before starting the procedure helps to wake up the baby.

Decoding and norms

Modern devices not only immediately after the end of the examination provide results for each of the determined indicators, but also evaluate the general condition of the fetus in points. We'll talk about scoring a little later, but for now let's look at what the basic terms mean and what it should be normally.

Basal rhythm

The contraction rate of a small heart is constantly changing. This is the first thing a woman will see. In order to average indicators that vary from 120 to 180 beats per minute, a parameter such as the basal rhythm was derived. During the first 10 minutes of the study, the device records changes in heart rate and displays the average basal value. This is what is indicated opposite the line “Basal rhythm” or “Basic heart rate”. It is considered normal in the third trimester if the base rate is between 110 and 160 beats per minute.

Rate variability

If the basal rhythm is an average value, then those same rapidly changing indicators of the baby’s heartbeat frequency are variability. The term used to denote this parameter is “oscillations,” which literally means “oscillations.”

These fluctuations can be fast or slow. Fast or (instantaneous) oscillations are fluctuations that occur with each beat of the baby’s heart. On the monitor, mom will be able to see them like this: 143, 156, 136, 124, 141 and so on, because the heart changes its rhythm every few seconds.

Slow vibrations are also different. If in 1 minute the baby’s heart changes its rhythm by less than three beats (it was 140, now it is 142), then we are talking about low variability and low oscillations. If in a minute the heartbeat rhythm changes to a number from 3 to 6 beats (it was 140, now it is 145), then we are talking about average variability. When heart rate changes by more than six beats per minute (was 140, now 150), they speak of high variability and high oscillations.

The norm is considered to be high and instantaneous oscillations.

If the baby’s device registers low variability and instantaneous oscillations, this may indicate serious pathological conditions in the baby. This is often observed with hypoxia.

Slow fluctuations can be monotonous (if the heart rate changed by no more than five beats per minute of study), transitional (the rhythm changed by 6-10 beats), wave-like (heart rate changed by 11-25 beats in 1 minute), and also galloping (more than 25 beats per minute). Wave-like slow oscillations are considered normal. Any other types of slow fluctuations are regarded as an alarming symptom. Jumping, in particular, occurs when the umbilical cord is entwined, and transitional ones occur when there is hypoxia.

Accelerations and decelerations

These are the same “teeth” and “dips” discussed by expectant mothers and visible on the graph. In simple terms, acceleration refers to raising the child’s heart rate by more than 15 beats per minute and maintaining this rate for 15 seconds or more. On the chart this is a rise. Decelerations are a decrease in rhythm by the same 15 beats per minute while maintaining the tempo for 15 seconds or more. On the chart they look like a failure.

2 or more accelerations for 10 minutes are considered normal. If the “peaks” on the graph are repeated with the same frequency and last the same amount of time, then this may be a sign of fetal distress. Decelerations are not considered normal at all. Most often they talk about possible hypoxia, but minor “failures” may also be a variant of the norm, it all depends on other CTG indicators.

Fetal movements

Many expectant mothers believe that the number of movements of the baby per hour is the main parameter that determines CTG. This is wrong. At least because there is no uniform standard for the number of movements a child makes per hour. Conventionally, it is considered a good sign if the baby makes 6-8 or more movements during the diagnostic hour. The number of movements can be affected by the mother’s mood at the time of the CTG, what she ate, and how her metabolism proceeds. The baby may be alert, or he may want to sleep. That's why the number of movements is looked at only in conjunction with other diagnostic results.

Contractions of the uterine muscles appear as smooth wavy lines on the graph, which is located under the fetal cardiogram graph.

Movements are noted there, but they have the appearance of sharp rises and peaks.

A small number of movements may indicate that the baby is sleeping or in a resting phase, as well as that he has severe disorders, for example, oxygen deficiency. But no conclusions can be drawn from this indicator alone.

Uterine tone

Many pregnant women are concerned about whether CTG will show the tone or hypertonicity of the uterus. The answer is not as simple as it seems. As mentioned above, CTG can be performed in two ways - external and internal. The external method in question does not give a clear answer as to whether a woman has increased tone. It only allows you to record individual contractions of the reproductive organ.

It is possible to accurately determine the level of pressure inside the uterine cavity (and with tone it increases) only by introducing a thin sensor electrode into the uterine cavity. During pregnancy, this is understandably impossible if the amniotic sac is intact and unharmed. And during childbirth, there is usually no need for such a measurement, because the baby is already ready to “go out”, and external CTG measurements will be informative, which will tell about his heartbeat and activity.

Therefore, by default, intrauterine pressure is considered to be 8-10 millimeters of mercury.

If the program, when assessing the contractility of the uterus, shows higher values, they talk about tone, but indirectly and very carefully.

Contractions – true and false

Contractions are contractions of the muscles of the uterus, and they are displayed on the CTG graph. Moreover, both real contractions that accompany the birth process, and false or training contractions that precede the onset of labor, sometimes long before them. On the chart, real contractions are depicted as fairly large waves in the bottom line. The training ones will look similar, but the “waves” will be less pronounced, and the duration from the beginning to the end of the wave will be no more than a minute.

If we simplify all of the above, then the CTG norms at which we can say that everything is fine with the child can be displayed in the following table:

Possible violations and their causes

Like any other diagnostic examination, CTG, or rather its results, can raise a lot of questions, especially if the doctor says that “CTG is bad.” We will describe below what pathologies can be identified.

Sinusoidal rhythm

A CTG graph that resembles smooth, identical sinusoids usually does not inspire optimism among specialists. True, this happens quite rarely - once every 300-350 examinations; theoretically, cardiotocography shows a sinusoidal rhythm in only one woman.

The graph is completely free of decelerations and accelerations (rises and declines), the base heart rate is quite normal, the variability does not exceed 15 beats per minute. Such a schedule usually does not bode well. This is how a child behaves in case of severe Rh conflict, significant hypoxia of the fetus, in case of poisoning of the pregnant woman and baby with toxic substances or narcotic drugs.

If a woman has not taken poisons or drugs, the risks for the child increase. In this case, a sinusoidal rhythm may be a harbinger of imminent death. Almost 70% of children who demonstrated such sinusoids on CTG were stillborn or died in the first hours after birth for various reasons.

In order to judge the sinusoidality of the rhythm, like in the picture, The graph should be “drawn” for 20 minutes or more. In this case, the woman is urgently hospitalized to perform an emergency caesarean section and try to save the baby's life.

High fetal heart rate

If a child's heart rate is clearly elevated on CTG within 10 minutes and the baseline heart rate consistently exceeds the norm, we are talking about fetal tachycardia. In this case, great importance is paid to exactly how much the basic values are exceeded:

Heart rate = 160-179 beats/min – mild tachycardia;
Heart rate = 180 beats/min and above – severe tachycardia.

The reasons that can make a small heart beat so fast can be different. Most often, tachycardia is a sign of oxygen starvation. When a baby does not have enough oxygen, his compensatory mechanisms “turn on”, which are designed to saturate the tissues and organs with oxygen “for future use.” The heart begins to beat faster under the influence of stress hormones.

The baby in the womb may respond to a fever with a high heart rate. If the mother’s body temperature rises to at least 37.5 or 38.0 degrees, the baby will immediately demonstrate an increase in heart rate. If the mother is not sick and does not complain about a rise in temperature, the cause of such a CTG may be infection in the baby himself. Intrauterine infection causes the baby's immune system to begin producing antibodies and various auxiliary substances, which increase the baby's temperature and make his heart beat faster.

If the mother took any medications shortly before the study, the doctor must be informed about this.

Side effects of some medications include increased heart rate, and not just for the mother herself. Tachycardia can be observed in children of women suffering from malfunction of the thyroid gland. In this case, the baby’s body is affected by incorrect hormonal levels of the mother.

Slow fetal heart rate

A decrease in the baby's heart rate below normal values is called bradycardia. Heart rate is considered an alarming indicator if it remains at 100 beats per minute or less for 10 minutes of the study or more.

The heart rate may slow down if severe hypoxia, which poses a real danger to the baby’s life. Such indicators during the birth process indicate that the baby’s head was pressed tightly while passing through the birth canal. In the second case, bradycardia is considered a variant of the norm; it is called reflex arrhythmia. Some medications that the mother took on the eve of the test can also slow down the baby’s heart rate.

Monotonous heartbeat

Such a violation can be discussed when slow fluctuations (oscillations) do not exceed 5 beats per minute. There are no sharp fluctuations in the graph. If this schedule remains for 10-15 minutes of the study or more, the woman will definitely be asked to undergo additional examinations, for example, ultrasound with Doppler Doppler Doppler, because monotony in most cases “signals” about hypoxia and other unfavorable circumstances for the baby.

Fetal hypoxia - oxygen starvation

All expectant mothers know how dangerous and insidious hypoxia can be. A deficiency of oxygen, which the baby receives with maternal blood through the “mother-placenta-fetus” system, can lead to irreversible processes in the baby’s central nervous system and even provoke his death.

Signs of baby hypoxia on a cardiotocographic examination are a decrease or increase in heart rate.

At the early stage of oxygen starvation, the heart beats more often than normal; at the late stage of hypoxia, a decrease is observed - bradycardia.

A baby who suffers from a lack of oxygen, which is so important for its development, will “demonstrate” on CTG low variability, accelerations that will be exactly the same in duration and severity, a sinusoidal rhythm and sharp, very frequent movements, which doctors call “painful movements.”

If CTG reveals one of these signs, then the woman is referred for additional examinations. But detection of two or more alarming indicators is grounds for hospitalization the expectant mother and speedy delivery by cesarean section.

Score

A scoring system is used to summarize the results of cardiotocography. The assessment of each of the above parameters includes the assignment of a very specific number of points, which together give the final result. In obstetrics and gynecology, there are several criteria for “awarding” points.

Fisher scale

Of all the methods for calculating results, this is still considered the most accurate and correct. When scoring the Fisher scale, four main values are assessed - base heart rate, variability, acceleration and deceleration. This scale was supplemented by Dr. Krebs, who also suggested taking into account the number of fetal movements. This resulted in a clear and simple scoring system:

Evaluation table for the Fisher scale as modified by Krebs:

Indicator determined on CTG	1 point is awarded if:	2 points are awarded provided:	3 points are awarded provided:
Base heart rate	Less than 100 beats/min or more than 100 beats/min	100-120 beats/min or 160-180 beats/min	121-159 beats/min
Expressiveness of slow oscillations	Less than 3 beats/min	From 3 to 5 beats/min	From 6 to 25 beats/min
Number of slow oscillations	Less than 3 during the study period	From 3 to 6 during the study period	More than 6 during the study period
Number of accelerations	Not fixed	From 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
Movements	Not fixed at all	1-2 in half an hour	More than 3 in half an hour

It is considered normal on this scale if the condition of the fetus is assessed at 9-12 points. This means that the baby is doing well, at least during the time the study was conducted.

If the CTG result according to Fisher is 6-8 points, then the woman needs further CTG monitoring, because such an indication is a sign of the child’s troubles. However, it does not pose an immediate danger to the baby’s life. It is recommended to repeat CTG more often to monitor the dynamics.

The most alarming indicator according to Fisher is less than 5 points. This means that the child is in mortal danger; his death can occur at any moment. Usually, with such CTG results, they are not sent home, but immediately to the hospital, where within the next few hours a decision must be made on early delivery in order to give the baby a chance to survive. This is the very case in which remaining in the mother’s womb is more dangerous for a child than being born, even very prematurely.

FIGO scale

This scale was created by the International Association of Gynecologists and Obstetricians in order to “equalize” certain errors in the assessment of CTG criteria by doctors from different countries. This is the international gold standard.

FIGO score table:

Common Questions

What is PSP?

The conclusion that a pregnant woman will receive after undergoing cardiotocography will indicate that fetal PSP = a certain numerical value. It’s not too difficult to guess what PSP is. This abbreviation stands for “fetal condition indicator.” This is a kind of summary that is issued after analyzing all the data received. PSP is calculated not by a person, but by a special program, and therefore the personal factor and qualifications of the medical staff do not matter here.

PSP is calculated by complex mathematical algorithms, which the expectant mother does not necessarily need to know. It is enough to familiarize yourself with the general standards of PSP as such:

Normal – 1.0 and below. A deviation from the norm, which is considered insignificant, for example, 1.03 or 1.05, is a reason to double-check the data, conduct a CTG again, perhaps something just went wrong.

PSP = 1.1-2.0. These numerical values indicate initial disturbances in the condition of the fetus. In this case, CTG should be repeated once a week, the woman is prescribed treatment depending on the reasons that caused the disturbance (fetal hypoxia, placental insufficiency, etc.).

PSP = 2.1-3.0. Such indicators indicate that the baby feels severe discomfort, his condition leaves much to be desired. With such values in CTG, it is customary for a woman to be hospitalized in order to make a final decision in the hospital - to treat or give birth. If it is decided to continue the pregnancy, a cardiotocogram will be shown every 2-3 days.

PSP= 3.0 and higher. This result is very worrying. Most often, it indicates that the baby is in critical condition. The woman is hospitalized immediately, sometimes by ambulance, and within a few hours a decision is made to perform an emergency caesarean section to save the baby’s life.

Is the gender of the baby visible on CTG?

The child’s genital organs, like other features of his appearance and structure, are not indicated in any way on cardiotocography. The sensors that the doctor attaches to the belly of the expectant mother do not display on the screen an image of what is happening inside, they only “write” graphs.

To find out the sex of the baby, it is better to go for an ultrasound or donate blood for a non-invasive DNA test.

These methods will answer with great accuracy the question of who is growing in the stomach - a son or a daughter. Attempts to determine the sex of the child based on the heart rate, which is determined on CTG, cannot be explained by any scientific arguments. Popular rumor says that a boy's heart beats less often than a girl's heart . Traditional medicine can neither confirm nor refute this - such a pattern has not been studied.

How to do a CTG during pregnancy with twins?

This question interests many, but the answer is not so simple. One sensor can record parameters for only one baby. If there are two or more babies in the mother’s womb, this can cause many technical difficulties during the procedure.

To avoid confusion when assessing the condition of two or more babies, the doctor will first determine the location of each of them. Separate ultrasound sensors will be attached to the area close to the heart area of each baby. If there are two children, then there will be two ultrasound sensors, if there are three, then there will be three sensors. But there will be one strain gauge sensor, as in a normal pregnancy. Thus, the woman will receive two or three graphs, the same number of conclusions about the condition (PSP) of each of the babies she is carrying.

What is a positive and negative non-stress test?

Additional tests can make CTG results more accurate. CTG with functional tests can be prescribed separately if the results of the first study turned out to be “suspicious”, questionable or borderline (between normal and pathological). Tests are different. A stress test is a recording of the fetal reaction, its heart rate and other parameters after administering a small dose of oxytocin to a pregnant woman, causing uterine contractions.

Before the examination, a woman may be asked to walk briskly up the stairs and hold her breath from time to time; all these will be options for stress tests.

A non-stress test is when there is no load or provoking factors from outside on the child, and the baby will respond to its own movements by increasing its heart rate.

If there is no increase in frequency after movement, this is an alarming sign and the test is considered positive. If in 40 minutes the baby makes at least two movements with accelerations, then the test is assessed as negative, and this is considered normal.

What will the study show if the baby is sleeping?

If the examination is carried out at a time when the baby is in the resting phase, then, like a sleeping adult, his movements will be minimized. The CTG will record the heart rate, as well as episodic contractions of the uterus, but there will be no movements or they will be sporadic, and there will be no accelerations associated with them. In this case, the doctor will take all measures to wake up the “sleepyhead”; if this does not work, the woman will be advised to come for a CTG again, in a few days.

What will the study show if a woman has oligohydramnios?

Cardiotocography cannot confirm the fact of oligohydramnios (as well as polyhydramnios); this can only be clarified by ultrasound. However, if the fact of oligohydramnios is established, CTG will be done more often. If the results over time indicate intrauterine suffering of the child, then the woman will be indicated for early delivery. This is not always the case, and many expectant mothers with oligohydramnios receive excellent results from cardiotocography.

Can CTG harm the fetus?

Cardiotocography is considered a completely safe method for the child and mother. Despite this, many women argue that ultrasound is harmful, as is CTG, which also uses an ultrasound sensor. The harm of ultrasound radiation for the development of a child has not been proven. True, it is also not yet possible to assess the isolated consequences of exposure to ultrasound radiation on humans (after ten, twenty or forty years).

Thus, only illiterate actions of medical personnel can harm the baby, who can tighten the strain gauge belt on the pregnant woman’s stomach too tightly, causing mechanical compression and even injury to the fetus.

Do CTG parameters change from week to week?

There is no difference at what time CTG is performed. The parameters that are determined in this study do not depend on the height, head circumference, chest or length of the child’s limbs, as happens with ultrasound. Therefore, the CTG results at 33, 35 and 36 weeks will not be any different. If the child is comfortable and well, then this is what the graph will show.

Experienced obstetricians, however, note one curious detail - The baby's heart begins to beat a little less often at 32, 34, 36 and 38 weeks.

Is it possible to carry out the procedure at home?

Theoretically and practically, this is possible, but the cost of devices for cardiotocography is high (several hundred thousand rubles), and small amateur devices that only record the heart rate and do not record or analyze other parameters do not have much diagnostic value.

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

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

For information on how CTG is performed, as well as other useful information on studies of a pregnant woman, see below.

Cardiotocography (CTG) is a method for assessing the condition of the fetus during pregnancy based on recording the frequency of its heartbeats and their changes.

CTG is prescribed no earlier than after the 26th week of pregnancy, since in the early stages it is not possible to decipher the data obtained. As a rule, CTG is prescribed at the 32nd week of pregnancy. By this time, the fetal rest-activity cycle and the connection between fetal cardiac activity and manifestations of motor activity are established. CTG allows you to assess the state of the cardiovascular, muscular and central nervous systems of the fetus). CTG can also be used to record uterine contractions.

When is an unscheduled CTG examination necessary?

As has already become clear, a CTG is recorded once, if the pregnant woman is not worried about anything and the doctor sees no reason to prescribe an additional examination. But there are some pathologies during pregnancy that require special attention and monitoring of the state of the fetal and uterine systems. These include:

1. The presence of a pathological version of planned tocography. Pathology of the fetal heart rate was noted. In this case, CTG is recommended to be repeated.

2. Unfavorable course of previous pregnancies. Situations when a woman’s obstetric history is burdened (miscarriages, problems with pregnancy, gestosis, fetal development abnormalities, congenital defects in previous children and other problems). This is a sufficient reason to record a CTG again, even if the current pregnancy is proceeding smoothly.

3. Situations when a pregnant woman feels disturbances in the behavior of the fetus. After all, every expectant mother feels and knows how her child usually behaves. Some children are very active and have short periods of sleep, while others sleep most of the day and are more active at night. A change in these rhythms may be a sign that the fetus is having problems.

4. Mother's illnesses. Those diseases that significantly affect the general condition of a pregnant woman, for example, influenza, acute respiratory infections, pneumonia, intestinal infections, etc. Then the need for CTG is determined by the attending physician together with the obstetrician-gynecologist.

5. The period after treatment of the fetus in utero. It is recommended to record a CTG for several weeks after inpatient or outpatient treatment.

6. Gestosis in pregnant women. This condition entails a change in the blood supply to the fetus (hypoxia). This may cause developmental delays in the unborn child.

7. Chronic infection in a pregnant woman.

8. Situations in which external factors have a detrimental effect on the fetus: smoking, alcohol and drug use by a pregnant woman.

9. Pregnant women with chronic diseases of internal organs: diabetes mellitus, coronary heart disease, arterial hypertension, obesity, chronic kidney and urinary system diseases, liver diseases, etc.

10. Post-term pregnancy.

How is the CTG procedure performed?

The fetal heart rate is recorded with a special sensor with a Doppler effect with a frequency of 1.5-2 MHz. The sensor generates an ultrasound signal that is reflected from the fetal heart, and the heart rate per minute is calculated through the heart monitor.

Before starting CTG, use a stethoscope to determine the area of best audibility of the fetal heartbeat on the anterior abdominal wall of the expectant mother, and then strengthen the sensor there. At the same time, uterine contractions are recorded using a special sensor mounted on the anterior abdominal wall in the area of the day of the uterus. Modern CTG machines have a special remote control with which a woman can herself record the movements of the fetus.

During CTG, the woman lies on a couch or reclines on a chair. The CTG procedure is quite lengthy and takes from 40 to 60 minutes. The CTG results are displayed graphically on a paper tape, which is then analyzed by the doctor and gives an opinion on the condition of the fetus.

The optimal time of day for cardiotocographic examination of the fetus is from 900 to 1400 and from 1900 to 2400 hours. It is at this time that its biophysical activity is maximally manifested.

It is not recommended to conduct CTG on an empty stomach or within 1.5-2 hours after eating. If, for some reason, the recording time is not observed, the results are considered unreliable. Because the child’s body (in utero) directly depends on the condition of the mother. After eating, glucose levels increase, which affects the activity of the fetus and its ability to respond to external stimuli.

Types of CTG

Depending on the method of obtaining information, CTG is divided into non-stress and stress tocography (functional tests).

Non-stressful includes:

1. A non-stress test involves recording in normal intrauterine conditions of the fetus. During it, the child’s movements are recorded and noted on CTG.

2. The method of movement determines the motor activity of the fetus indirectly, by changing the tone of the uterus. It is used in the absence of a sensor that detects movement.

Stress cardiotocography (functional tests) is prescribed if the results of a non-stress examination are negative. Allows you to more deeply understand a possible problem that has arisen in the fetus and the pregnant woman.

1. Tests simulating the birth process:
- Stress oxytocin test. Contractions are induced by intravenous administration of the hormone oxytocin and the response of the fetal heartbeat to moderate uterine contractions is monitored.

Nipple stimulation test (mammary test). With this technique, contractions are stimulated by irritation of the nipples. The pregnant woman herself causes irritation until the moment when contractions begin. This moment will be visible from the cardiograph readings. This method is safer compared to the previous one. It also has significantly fewer contraindications.

2. Tests affecting the fetus:
- An acoustic test allows you to determine the reaction of the fetal cardiovascular system in response to sound stimulation.

Palpation of the fetus - a slight displacement of the presenting part of the fetus (pelvis or head) is performed above the entrance to the pelvis.

Functional tests that change the parameters of the blood flow of the fetus and uterus. Today they are practically not used.

Main indicators of CTG

Basal rhythm (BHR or HR) is the average heart rate. Normally it is 110-160 beats per minute in a calm state, 130-190 during fetal movements. Heart rate should not go beyond the normal range and be smooth.

Rhythm variability (heart rate range) is the average deviation of the rhythm from the basal one. Normally it ranges from 5 to 25 beats per minute.

Acceleration – peak of heart rate acceleration (looks like tall teeth on the graph). Normally – 2 peaks per 10 minutes during the period of fetal activity. Amplitude – 15 beats per minute.

Deceleration is a slowdown in heart rate (looks like depressions on the graph). Normally, they should be absent or quick and shallow. The number of decelerations should tend to zero, the depth should not exceed 15 beats per minute, and there should be no slow decelerations at all.

Fetal condition indicator (FSI) is normally less than 1, from 1 to 2 - minor violations, more than 2 - obvious violations.

The tocogram shows the activity of uterine contractions. Normally, uterine contractions should be no more than 15% of the BHR.

CTG assessment by points

When deciphering CTG, each indicator is assessed by the number of points, the values are summed up:

9-12 points – the condition of the fetus is normal. Further observation is recommended.

6-8 points - moderate hypoxia. A CTG repeat is required the next day.

5 points or less – severe hypoxia, life threatening. An emergency caesarean section may be recommended.

Problems that CTG helps to identify

1. Entanglement of the umbilical cord or its compression, which subsequently causes a decrease in the supply of oxygen to the fetus from the mother. In addition, sufficient nutrients will not be delivered through the blood. All this affects the growth and development of the fetus.
2. Violation of fetal heart rhythm. Irregular heartbeat can occur in the presence of defects and stigmas in the development of the cardiovascular system of the unborn child.
3. The fetus experiences hypoxia. Even a slight disruption in the delivery of oxygen or nutrients through the umbilical cord blood will be recorded on CTG.

In cases where, after performing a CTG, the doctor notices deviations from the norm, the woman may be prescribed additional ultrasound and Doppler sonography. Sometimes you need to undergo a course of treatment and repeat the examination over time.

Does CTG harm the fetus?

There is not a single study proving the harmful effects of CTG on the fetus or the body of a pregnant woman. The subjective opinion of women suggests that children “feel” the examination. Some suddenly calm down, while others begin to become overly active. Doctors believe that this reaction is due to the fact that children hear unusual sounds and feel uncharacteristic touches (fixing sensors on the stomach, etc.).

Errors in CTG recording that distort the result

There are a number of situations when pathological changes are recorded on a CTG recording in an absolutely healthy woman and fetus.

1. Overeating before the examination.
2. Recording made while the child is sleeping.
3. Maternal obesity. Through a significant layer of subcutaneous fat, it is difficult to listen to the fetal heartbeat.
4. Excessive physical activity of the child.
5. Situations involving insufficiently tight fit of the sensors, or drying out of the special gel.
6. Multiple pregnancy. Recording the heartbeat of each fetus individually is very problematic.

Pathological rhythms determined by CTG

There are quite a lot of pathological rhythms, but it’s worth focusing on the two main ones that occur most often.

A monotonous rhythm is recorded when the fetus is sleeping or when the supply of oxygen to it decreases. Why is the hypoxia situation very similar to a dream? The answer is quite simple. All fetal systems operate in “energy-saving mode” to save missing substances and oxygen. Consequently, the heartbeat will have a monotonous rhythm.

Sinus rhythm is a recording where the heartbeat either quickens or slows down. This picture is typical during constant fetal movement. If the child behaved calmly and the sinus rhythm was recorded, this may indicate a serious condition of the fetus.

You should not try to decipher CTG yourself. This should be done by a specialist, because only an obstetrician-gynecologist has the necessary knowledge and can suspect a problem. When assessing the condition of the fetus, taking into account CTG data, it is necessary to remember that CTG does not make an accurate diagnosis, but primarily reflects the reactivity of the fetal nervous system at the time of the study. Changes in fetal cardiac activity only indirectly indicate possible pathologies. The results of CTG should not be reduced only to the presence of varying degrees of hypoxia in the fetus.

Even if not all CTG indicators are within the normal range, only a doctor can give a correct assessment of the child’s condition, taking into account the results of other examinations in addition to CTG.

When to do CTG during pregnancy to get the most complete information about the child living inside? What do you need to know about how CTG is done correctly, what will provoke the occurrence of errors that so frighten future parents? We will cover these and some other questions in the article.

When is CTG indicated?

From how many weeks is CTG performed?. By order of the Ministry of Health, the first CTG can be done from the 28th week of pregnancy. If there is a suspicion of a critical situation with the fetus, the study can be carried out earlier. But in these cases, the device will only record the fetal heartbeat itself.

It is not yet possible to assess how the baby reacts to uterine contractions, how the pattern of the heartbeat changes depending on the fetal movements themselves and some other factors.

Until the 28th week, there is still no full interaction between the heart and the autonomic nervous system. And, in fact, this study is being conducted to evaluate all these indicators.

But, Basically, the first CTG is done at 30-32 weeks. It is for this and later periods that diagnostic criteria have been drawn up, by which the condition of the intrauterine fetus is assessed.

How many times is CTG done during pregnancy?

This examination is not the main one in terms of determining the tactics of delivery and pregnancy management, but only auxiliary. CTG is prescribed during pregnancy, if it is proceeding normally, and there are no abnormalities on ultrasound, once or twice in the third trimester.

According to the order of the Ministry of Health, the answer to the question of when to do CTG during pregnancy sounds something like this: “If the pregnancy is progressing normally, then CTG is done once every ten days, starting from the 28th week.” For cases of complicated pregnancy, there are the following recommendations:

in case of post-term pregnancy - once every 4-5 days after the expected due date has approached
if there is incompatibility by Rh factor or blood group - 2 times a month
for polyhydramnios – once a week
for heart defects - every week
fetoplacental insufficiency - at least 1 time per week
for thyrotoxicosis, regardless of whether there is a goiter or not - once a week
for a large fetus, narrow pelvis, multiple pregnancy, previous rubella, hypertension, infections of the genitourinary system of a pregnant woman - as necessary, but at least 1 time in 10 days
with placenta previa without bleeding, in expectant mothers over 35 years old - the criteria are the same.

When to do a CTG during pregnancy is mainly left to the discretion of the obstetrician-gynecologist who is monitoring your pregnancy. He is most often guided by the following criteria:

if uncomplicated pregnancy, CTG - twice a month from 32 weeks
if there are complications or aggravated background in pregnant women, then CTG is performed from the 28th week, with an interval of 5-7 days, and also when any changes have occurred in the woman’s condition
if the pregnancy is complicated, previous CTG results are unsatisfactory, it is recommended to hospitalize the pregnant woman, and then decide on the interval at which CTG should be done individually, based on the obstetric situation.

Is it possible to do CTG before the birth itself?

CTG before childbirth can be done directly on the day of the expected birth or at the onset of labor.

If the doctor has not yet fully decided on the tactics of labor management, a cardiotocogram study can help him with this: such a study is done quite often (it is possible to use it daily).

If the tactics of delivering the child through the natural birth canal have been chosen, and the pregnancy is carried beyond term, CTG is done as follows:

on the day of expected birth or the next day
after 4-5 days if the results were good
in another 4-5 days.

At 41-42 weeks, if labor has not developed, a council of doctors reconsiders the tactics of labor management. Doctors decide whether to induce, wait, or proceed with surgical resolution of labor. CTG data in this case plays an important role, since they more clearly demonstrate the condition of the fetus.

The need for CTG during labor

CTG during childbirth should be performed in all women, regardless of their obstetric situation.

During the period of contractions, it is recommended to perform the study every 3 hours in case of uncomplicated labor, and in complicated cases - more often or continuously. The second period for everyone should be carried out under continuous CTG control.

During childbirth, CTG is especially informative, as it shows how the baby tolerates the load. If normally there should be 110-160 heart contractions outside of a contraction, then with hypoxia there is first an increase in heart rate (more than 160), then a decrease in heart rate.

This is a signal to obstetricians that they need to speed up the birth of the baby. Depending on the situation, this “acceleration” can be accomplished by obstetric assistance, the use of forceps or a vacuum extractor, episiotomy or perineotomy. If signs of hypoxia are observed when the head is not yet in the pelvis, an emergency caesarean section is possible.

CTG signs of hypoxia during labor also mean that you need to call a resuscitator, since the newborn may need his help.

How to do CTG during pregnancy

It is correct to do CTG with the woman in a semi-sitting position or on her left side, since if she lies on her right side, the pregnant uterus can press on the inferior vena cava, and this can lead to complications. Before performing a CTG of the fetus, they use a stethoscope to listen to the place on the woman’s abdomen where the baby’s heart beat can best be heard, because it depends on how he turns.

A CTG sensor is placed at the place where the heartbeat is best heard, and it is fixed to the stomach with a belt. The CTG procedure during pregnancy is not performed within an hour after a meal or intravenous glucose administration, since such things usually stimulate the activity of the fetus. Fasting CTG is also not performed. The optimal range is 2-3 hours after meals. If the parameters are not met, there may be errors in the tocogram.

Duration of CTG

How long does it take to do a CTG? This is usually a rather lengthy procedure. It takes from half an hour to an hour and a half (according to orders, at least 40 minutes). If the tocogram is normal, this is another scheduled examination, the previous one was carried out less than 10 days before and was normal, recording can be stopped after 10 minutes.

How and who analyzes CTG

CTG analysis during pregnancy is initially carried out automatically: the CTG device analyzes the rhythm at rest, movements, with minimal contractions that occur at any stage (the only difference is their frequency). The rating is on a 10-point scale:

10-8 points – the child is healthy
5-7 points means that the condition of the fetus is borderline, and if measures are not taken, a disaster may occur
4 points and below reflects severe fetal hypoxia

The tocogram must also be assessed by a doctor; a diagnosis is not made based on hardware assessment.

Approximate CTG norms at 32 weeks

Basal heart rate: 120-160 beats/min
Contraction frequency variability: 10-25 beats/min
Accelerations: 2 or more per 10 minutes of recording
Average acceleration amplitude: 12-17
Rapid decelerations on CTG at 32 weeks of pregnancy: the number should be about 0-2
Slow decelerations: 0
Number of fetal movements: more than 5 in half a minute.

Normal CTG at 33 weeks

Basal rhythm is the same as at 32 weeks
Basal rate variability from 10 to 25 per minute
A very small amount, or better yet, no or decelerations; they must be “quick.”
Accelerations: 2 or more during a 10-minute recording.

The basal rhythm should not be less than 110 and more than 160 beats/minute. CTG readings at week 33 should not show contractions; there should definitely be accelerations.

CTG at 35 weeks and later

The CTG norm at 35 weeks consists of the same indicators, their range should be the same as at 32 or 33 weeks. Basal rhythm: 119-160 beats/min; the amplitude of variability is from 10 beats to 25 per minute. Character of the rhythm: undulating or saltatory.

There may be more rapid decelerations, since this to some extent reflects scrum activity. Fetal movements, if he is not sleeping at the time of the study, are more than 60 during this entire time.

CTG norms at 36 weeks should not differ much from those at 35 weeks

Fetal CTG normal 36 weeks should show

Basal heart rate: same as for other periods
Heart rate range: 10-25 per minute
Rhythm: undulating or saltatory
Accelerations: more than 10 in 40 minutes
Fast decelerations: up to 5 during the entire time
There are no late decelerations or sinusoidal rhythm on CTG at 36 weeks of gestation.

CTG interpretation at week 37 is carried out according to the same indicators. The norms should not differ much from those presented at week 36.

What does a CTG picture look like at 38 weeks of pregnancy?

The same criteria must be met for this entry. The main thing is that there are accelerations (at least 2 in 10 minutes), there are no late decelerations or sinusoidal rhythm, the amplitude of variability is no more than 25 and no less than 10 beats/min. PSP here is up to 1.0 normally.

CTG criteria at 39 and 40 weeks of pregnancy are the same. The duration should not in any way affect the frequency and nature of the basal rhythm, or the amplitude of variability. Also, there should be no slow decelerations, and very few fast ones. PSP also ranges from 0 to 1.0. There may only be a decrease in the number of movements and the appearance of contractions is described, which means the body is preparing for childbirth.

Displaying uterine contractions on CTG

Contractions on CTG are displayed on a separate graph on the cardiotocogram. A certain amount of them is allowed, which increases with increasing gestational age. The results of CTG must be seen by your doctor, who determines the tactics of labor management.

So, if a pregnant woman is expected to give birth by cesarean section, the increase in contractions is an indication for going to the hospital and quickly deciding on delivery.

Contractions on CTG during a period of 36 weeks or more, if they are not accompanied by a decrease in the fetal heart rate (that is, there is no hypoxia) and/or a deterioration in the CTG score, are normal.

Errors of CTG

The main error is the entry “CTG criteria are not met.” This means that the sensor was unable to reliably assess the rhythm and pattern of the fetal heartbeat. The study must be repeated. When to do this - every other day or every other week - depends on the obstetric situation, so consult your doctor.

When is CTG prescribed, and when is Doppler

CTG and Doppler are different research methods that are often prescribed almost simultaneously.

CTG helps to assess the condition of the fetus, whether it has enough oxygen (this can be seen by how it reacts to uterine contractions and its own movements).

Doppler measures the diameter of blood vessels in the mother-placenta-fetus system, the state of blood flow in the placenta, and its speed. It visualizes vessels and blood flow in them, while CTG indirectly shows how oxygen is absorbed from normal or pathologically altered vessels.

Research is interrelated, and its assessment must be carried out in a comprehensive manner. So, Doppler may show signs of pathologically changed vessels, and CTG may be normal. This means that the pregnant woman needs to be monitored, treated with medication, and repeated CTG done, but not rushed into delivery.

What tests are there for CTG?

In cases where CTG should resolve some doubts about the well-being of the fetus, tests are performed during it. They can be stressful, involving the introduction of special substances into the pregnant woman’s blood that stimulate the child’s motor activity.

There is also a non-stress test with CTG. At the same time, the reaction of the baby’s cardiovascular system to his own movements is measured. This test has 3 assessments:

A positive (non-stress) test is a bad result. This means that there were only 2 or fewer heart rate increases during the 40-minute study. Moreover, such a reaction occurred for less time than 15 seconds, and the increase itself did not exceed 15 beats per minute (that is, if it was 145, it became 160 beats per minute or less).
The result may also be a false positive, when there was no particular increase in heart rate simply because the baby was sleeping. Then the CTG needs to be repeated after a few (2-4) hours.
Negative result: within 20 minutes there were more than 2 increases in heart rate, they lasted more than 15 seconds, and their difference from the main heart rate rhythm exceeded 15 beats per minute.

Is it dangerous to do CTG for a child?

You may have heard that CTG is harmful during pregnancy only from unreliable sources that have nothing to do with medicine. This research method has been proven to be completely safe for the fetus. Just don’t overuse it, as ultrasound can be unpleasant for the baby’s hearing organ to perceive. Many people are looking for an answer to how much CTG costs during pregnancy. According to our information, the average price in Russia is about 800-1200 rubles.

So, now you know when to do CTG during pregnancy. Indications regarding the frequency of examination should be determined by the obstetrician, based on your situation. But, if you are prescribed it, be sure to do it: this way you will know that everything is fine with the baby. How CTG is done is also described in the article. This information will be useful so that the expectant mother knows what may cause errors in the study and can avoid them.