Update: December 2018
When the expectant mother feels the movements of the fetus, it is wonderful: the pregnant woman knows that the baby is doing well. But according to motor activity it is impossible to assess the possible onset of intrauterine suffering in a child.
In order to detect and prevent problems in time, it is necessary to use ultrasound research methods (CTG, ultrasound and Doppler). Cardiotocography (CTG) of the fetus is a simple and available method assessment of the baby’s heartbeat, with the help of which you can notice the initial signs of oxygen deficiency.
In addition, it is possible to identify changes in the muscle tone of a woman’s uterus, which can cause premature birth. CTG is a technique for recording uterine tone and heart rate on special calibration paper. That is, there are 2 graphs; some devices can record the child’s motor activity:
- heartbeats recorded by ultrasound
- uterine tone determined by a strain gauge
Is cardiotocography harmful to the fetus?
This is an absolutely safe procedure for both the fetus and the woman, does not cause discomfort and can be performed according to indications even daily (in case of fetal hypoxia), to assess the effectiveness of the therapy and make a decision on emergency delivery.
Indications for CTG
The most informative method is in the last trimester of pregnancy. It is after 30 weeks that the biorhythms of the fetus are fully established (cycles “activity-sleep”) and a specific reflex is formed (increased heart rate with fetal movements), by which one can judge the full support and normal intrauterine development of the child (see). The main indications for CTG during pregnancy include:
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Complicated pregnancy:
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Diseases in the fetus identified by ultrasound examination:
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Serious illnesses in a pregnant woman:
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In the cases listed in the table, CTG should be performed more often, up to daily. Fetal condition and effectiveness labor activity Cardiotocography also allows evaluation in real time.
Research methodology
Most often, the examination is carried out at 32 - 34 weeks of pregnancy. CTG is performed in the pregnant woman's supine position with a small bolster under the right side (the optimal position is a slight turn to the left side). It is possible to perform CTG in a position lying on your side, or sitting, leaning back in a chair.
When CTG is done, the study is carried out using sensors with a frequency of ultrasonic waves of 1.5-2 MHz, which is absolutely safe for the fetus even with prolonged exposure. Any modern device has the ability to assess the vital functions of two fetuses at the same time, which is used in women with twins.
Types of devices
Medical facilities have various options for assessing your baby's heartbeat. Most often, the doctor simply listens to the baby’s heart rhythm using an obstetric stethoscope, but if there is any doubt (or if there is evidence), it is necessary to use a special device. What types of CTG devices are there?
- CTG without automatic analysis
These outdated devices are generally quite rare in modern hospitals, but they can still be found in remote corners of our country. The main inconvenience of these devices is that the doctor must independently evaluate the fetal heartbeat graph. If the doctor has experience and masters this technique, then the effectiveness of these devices is no lower than that of new CTG devices.
- CTG with computer analysis
Modern cardiotocographs not only record the graph, but also independently process the data. The doctor only needs to read the finished result and decide on the need for treatment. This version of CTG is used most often in medicine.
- KTG-online
The modern mobile era offers an excellent option for monitoring the baby using a special sensor attached to the skin of the abdomen and a smartphone connected to the Internet. Information about the fetal heartbeat is transmitted in real time to a web portal, processed and provided in the form of a ready-made report to the doctor. Unfortunately, online CTG is still rarely used.
Interpretation of CTG: pathology or normal
The table below shows the assessment of the fetal condition according to CTG, proposed by Dr. Savelyeva, which takes into account all indicators:
- basal rhythm - average fetal heart rate
- variability - changes in the frequency and amplitude of the heart rhythm (deviation from the basal rhythm frequency
- acceleration - acceleration of the heart rate from the basal rate by more than 15 beats, lasting over 10-15 seconds.
- deceleration - a decrease in the fetal heart rate from the basal rate by more than 15 beats, lasting more than 10 seconds.
- fetal motor activity
A bad CTG during pregnancy will occur if the following indicators are detected:
- prolonged increase in fetal heart rate (tachycardia) more than 160 beats per minute
- decrease in baby's heart rate to less than 110 beats per minute
- increased rhythm variability with an amplitude of more than 25 beats per minute
- reduction in variability below 5 beats per minute
- sinusoidal rhythm, in which a uniform and monotonous heartbeat occurs without any fluctuations or changes in variability
- appearance of decelerations
After counting the points, the condition of the fetus is assessed:
- 5 or less - a state of fetal hypoxia, the child experiences oxygen starvation
- 6, 7 points - the first signs of fetal hypoxia
- 8, 9, 10 points - no hypoxia, the child feels well
Motor activity is not taken into account in Savelyeva’s method, but you should know that increased, excessive fetal mobility or, conversely, its absence, indicates the presence of oxygen starvation in the fetus.
However, even when deviations are detected, this does not always indicate serious problems in a child. It is necessary to take into account not only CTG during pregnancy, the interpretation of which will indicate the presence of hypoxia in the baby, but also the duration of pregnancy, the presence of complications in the pregnant woman, data from ultrasound examinations and Doppler measurements.
What to do with a bad CTG
All methods for assessing the condition of the fetus are required for the timely implementation of therapy aimed at reducing fetal hypoxia; the results of CTG during pregnancy are among the most informative for this. This is especially true in the case when the examination reveals severe fetal suffering and it is necessary to quickly make a decision to save the child’s life. Typically, in this situation, it is done C-section on an emergency basis.
If moderate signs of insufficient blood supply to the fetus occur, detected by CTG, complex treatment is carried out. It is optimal to do this in a hospital, in the antenatal department.
- Complete rest is indicated for the pregnant woman
- Improving fetoplacental circulation (blood flow between mother and fetus)
Medicines are used that reduce the tone of the uterus, which leads to better blood flow from the uterine vessels to the placenta. To do this, use Ginipral solution for intravenous administration in the form of daily droppers. Good effect They give antispasmodics (,). Also shown are Magne B6, Bricanil.
- Preparations to improve cellular permeability to oxygen
Appointment required medicines, improving metabolism - glutamic acid, vitamins C, E, glucose, neuroprotectors, antihypocanthics. As well as drugs that improve cellular permeability - Essentiale Forte, Lipostabil.
- Reduced blood viscosity
Considering that small vessels predominate in the placenta, it is necessary to improve blood fluidity to prevent the formation of small blood clots. Curantil, Trental, Actovegin, Reopoliglucin are prescribed, you can use small doses of Aspirin - ¼ tablet twice a day (see)
- Treatment of pregnancy complications and women's diseases
If a pregnant woman has high blood pressure, antihypertensive therapy is indicated. With anemia, it is necessary to increase the level of hemoglobin, which carries blood with oxygen to the fetus (see). Correction of endocrine disorders and renal dysfunction in women is important.
- Accelerating the maturation of the baby's lungs
When the pregnancy is up to 36 weeks, the fetus's respiratory system has not yet matured, and the baby may have problems with its first breath. If there is a risk of early delivery due to severe fetal suffering, then the development of the child’s lung tissue should be accelerated. For this purpose, injections of a corticosteroid (dexamethasone) are used.
- Oxygen cocktail
A woman can independently take an oxygen cocktail, which can be purchased at pharmacies or special departments of stores for mothers and babies (“Ecotail”). The cocktail is made very simply; the kit includes gas cans and bags of mixture. By diluting the mixture with apple juice, you get a solution that is filled with oxygen through a special tube, 5 minutes and the cocktail is ready. In case of hypoxia in a child or for prevention, it should be used 3 times a day after 30 weeks (or even the entire pregnancy with 15 day breaks).
- After improvement
When signs of fetal hypoxia decrease and the pregnant woman’s condition improves, aqua gymnastics is recommended, breathing exercises, Ural Federal District.
Complex therapy for fetal hypoxia is carried out under regular CTG monitoring. If treatment is ineffective or the cardiotocogram worsens beyond 28 weeks, doctors may decide on emergency delivery to save the baby’s life.
What is CTG in pregnant women? Cardiotocography (CTG) is a method of functional study of the condition of the fetus in the womb of a pregnant woman, which is based on a sequential recording of the child’s heart rate and its changes in accordance with the contractile movements of the uterus, the influence of environmental factors and the activity of the baby himself.
This recording of the heartbeat is carried out within 15 minutes and can be carried out both in a calm state of a woman outside the labor process, and during labor and childbirth. This feature makes CTG quite effective and useful method to resolve the issue of delivery tactics.
In addition, the information content of CTG is very important in determining the frequency of contractions of the smooth muscle cells of the uterus and the child’s reaction to these contractions.
Cardiotocography is an effective research method for excluding or timely determination of pathological conditions of mother and child posing a threat to the course of pregnancy and to the future health of the newborn baby, such as intrauterine infection of the fetus, oligohydramnios, congenital abnormal development of the cardiovascular system, fetoplacental insufficiency and the threat of labor starting earlier than planned.
Main indications for CTG
- A woman with Rh-negative blood is at risk of developing hemolytic disease newborns.
- A history of premature labor, miscarriages and abortions.
- Feelings of decreased fetal movements in the pregnant woman herself.
- Complications during pregnancy (multiple fetuses, polyhydramnios, oligohydramnios, fever or low-grade temperature in a pregnant woman, incorrect presentation of the baby, post-term pregnancy).
- Disorders in the child that were previously found with (developmental delay, disorders in amniotic fluid, decreased activity, pathological changes in blood circulation in the placenta, the baby’s size is too large or small and does not correspond to the month of pregnancy).
- Endocrine and systemic diseases in pregnant women (types 1 and 2, diseases of the cardiovascular system).
This method of studying the condition of a child during his intrauterine life is safe, since the sensor reproduces an ultrasonic wave of weak strength, does not cause negative effects on the baby.
At what stage is fetal CTG done?
The use of cardiotocography can begin with approximately , but high-quality and informative recording of the above parameters that characterize the state of the child in the womb is only possible with .
This is due to the development of periodically alternating cycles in the baby, when he is active or calm in motor terms. The baby is most active in the period from 9 to 14 pm, as well as from 19 to 24 pm.
How to prepare for CTG during pregnancy? CTG is contraindicated after meals, since elevated levels can significantly affect the fetus, increasing its movements and reaction to external environmental stimuli.
How to do fetal CTG during pregnancy
Cardiotocography is performed using specialized sensor, which has an ultrasonic effect and is based on the effect.
This device is tightly secured to the front of the pregnant woman's abdomen, where the baby's heart sounds are most clearly heard. Such an area can be preliminarily determined without any problems using an obstetric stethoscope.
The sensor, producing a signal in the form of an ultrasonic wave, directs it towards the baby's heart in the womb. The wave is reflected from the heart, which is perceived again by the same sensor in the end. The received information is converted into values fetal heart rate per minute. The research results are reproduced sound, light and graphically on tape.
If the pregnancy is normal, CTG is performed no more than once a week. In case of a complicated pregnancy, but with good results from previous methods of fetal examination, this procedure is performed with a pause of an average of 6 days.
If it has developed child hypoxia in the womb, CTG is indicated for daily or every other day for constant dynamic monitoring of the child’s condition and timely adoption of measures for emergency childbirth.
Interpretation of fetal CTG results during pregnancy
The results of the cardiotocography analysis are assessed specialist in a number of indicators, which include the basal rhythm, variability, acceleration, deceleration and, finally, the activity of the baby’s movements in the womb. All this is depicted at the end of the manipulation on paper in the form of graphs of various shapes.
How to decipher CTG? You should not try to decipher your CTG yourself, since you, not being a doctor, will make a mistake when deciphering the fetal cardiotocography in calculating points based on the results, which, of course, can harm the child.
Basal rhythm is the average value of the fetal heart rate. Normally, the basal rhythm reaches from 110 to 160 heart beats per minute when the baby and pregnant woman are calm. When the child moves, the frequency of contractions increases to values ranging from 140 to 190 beats.
All normal values of the basal rhythm indicate absence of hypoxic condition baby's body. And the increase, as well as the decrease, are a clear sign of fetal hypoxia, which, first of all, is detrimental to its nervous system, although it is not yet fully developed.
Variability(in other words, amplitude) - a change in the value of the heart rate frequency and its amplitude relative to the obtained values of the basal rhythm of the baby’s heart.
Outside of pathology, the heart rate of a child in the womb should not be constantly the same and monotonous, which is clearly visualized by the continuous change of numerical values on the monitor during CTG. Normal changes in the relevant parameters should range from 5 to 25 beats per minute.
An increase in amplitude may indicate the same fetal hypoxia or, which is undoubtedly a pathology. Reduced amplitude values may be normal if the baby is in a calm state at the time of CTG. In order to “wake up” the baby, the mother can simply eat some sweetness.
Acceleration(increase) - an increase in the number of heart beats compared to the level of the basal heart rate. The magnitude of acceleration is expressed on the cardiotocogram in the form of teeth; normally it is at least 2-3 times within 15 minutes. It is permissible to increase the number of repetitions up to 4 times per half hour. What is pathological is their complete absence during the specified time period.
Deceleration(decrease) – a decrease in heart rate values in comparison with the level of basal heart rate. The magnitude of deceleration is expressed in the form of dips (“negative” teeth). Normally, such manifestations on the graph shouldn't be present or be insignificant in depth, duration and occurrence.
The deterioration of the baby's condition in the womb can be confirmed by the occurrence of decelerations after 20 minutes of examination. Also a bad result is their repetition and different appearance throughout the entire chart. All this may indicate decompensated fetal stress.
Overall transcript norms of CTG results the fruit looks like this:
- Basal rate – 120-159 per minute at rest.
- Variability from 10 to 25 beats per minute.
- 2 or more accelerations within 10 minutes.
- No decelerations.
Pathological CTG looks like this:
- Basal rhythm – less than 90 and more than 180 per minute.
- Variability less than 5 beats per minute.
- Absence or small number of accelerations.
- Availability different types decelerations.
Fisher ten scale
The results of cardiotocography are assessed by specialists on a ten-point Fisher scale, which is based on assigning points from 0 to 2 to each of the above indicators. These scores are summed up, and a general conclusion is made about the information content of CTG and the presence of pathological changes in the fetus. The so-called "indicator of fetal condition"(PSP).
- If total points CTG compiled from 1 to 5, then the baby’s condition in the womb is poor, he experiences hypoxia (lack of air).
- What does it mean if the sum of CTG points is 6-7 ? The child shows initial signs of developing oxygen starvation.
- What does it mean if the sum of CTG points is from 8 to 10? This indicates the normal and good condition of the baby.
With a PSP of 1-5 points, immediate delivery is indicated; with a PSP of 6-7 points, repeated CTG is indicated; with a PSP of 8-10 points, continued periodic monitoring of the pregnant woman and fetus through this method research.
How can pregnancy duration affect CTG readings?
If CTG is performed earlier than 29-32 weeks of pregnancy, it can become uninformative and meaningless, since it is by this period that the fetus develops a sleep-wake pattern, and previously it manifests itself only by calmness in the mother’s belly.
Depending on the week, the indicators are approximately the same, but the shorter the week, the higher the variability (amplitude).
The fact that the doctor did not like the results of cardiotocography does not mean a final determination of fetal hypoxia and pathology in principle. There are cases when young doctors without sufficient work experience incorrectly interpreted the information contained in the received graph, although everything was completely normal for the baby and his mother.
Therefore, you should not rush and immediately panic when you get a bad result. But you shouldn’t relax, as this may actually indicate a real pathology that requires immediate treatment and action on the part of medical professionals.
Most likely, if the results are alarmingly abnormal, the doctor will ask you to go to hospital in maternity hospital, where they will conduct regular CTG and will be able to quickly react in a dangerous situation.
How contractions appear on CTG
This study is required indicates the presence of contractions, since normally the uterus should react to the active motor activity of the baby with its spasms. In addition, the uterus has the ability to spontaneously contract. On CTG, in response to contractions, a decrease in the number of baby’s heartbeats and deceleration will be visible, which occurs in rare cases.
The second curve (hysterogram) reflects the increase in the force of contraction of the myometrium (muscular layer of the uterus) during contractions. The higher it is, the stronger the contractions. Some women in labor do not feel contractions; CTG helps determine their strength and frequency.
What is the Fetal Reactivity Index?
This indicator tells the specialist about the state of the fetus’s nervous system reactivity to external influences, which, first of all, affects the state of the cardiovascular system.
Calculation is carried out using a point system and further interpreted:
- 0 points means an absolute lack of reactivity in the baby.
- 1 point means severe disturbances in the body's reactivity.
- 2 points mean severe disturbances in the baby’s reactivity.
- 3 points indicate a moderate degree of impairment in reactivity.
- 4 points indicate the initial stage of the pathology of the child’s reactivity.
- 5 points means normal reactivity in the fetus.
What is a non-stress test?
This type of research into the condition of the baby in the womb is test to determine cardiac activity according to the baby's movements.
A good result is a negative non-stress test (the presence of 2-3 increases in the number of heart contractions by about 15 beats per minute for 15-20 seconds). In the case of a positive or no result at all, we can conclude that the baby is in a hypoxic state, which, in fact, may be a false phenomenon if at the time of the study the fetus was calm and sleeping. In this case, it is recommended to repeat the non-stress test.
Cardiotocography is one of the most accurate methods for determining baby hypoxia in the womb of a pregnant woman, which is very valuable for its timely diagnosis and taking measures to eliminate it. In the presence of hypoxia, CTG shows the following changes:
- Decreased or complete deficiency of fetal heartbeats.
- Increased heart rate when the fetus moves or the uterus contracts involuntarily.
Erroneous assessment of CTG results
Errors when interpreting information obtained using cardiotocography are certainly possible. For example, in case of hypoxia, but despite the fact that the baby’s tissues have already managed to adapt to it, CTG is not able to show this pathological condition. The same can happen if there is a sufficient amount of oxygen in the bloodstream, but the tissues cannot adequately accept and use it, which indicates actual fetal hypoxia.
The presence of errors obliges specialists to evaluate the results of CTG only in combination with the results of other studies carried out on a pregnant woman, and then make a final diagnosis.
Video about fetal cardiotocography (CTG)
We invite you to watch a video about fetal CTG. An obstetrician-gynecologist will tell you how and why this examination is carried out, how its results are evaluated, and what are the normal CTG indicators.
Any pregnant woman will sooner or later undergo a CTG procedure; some of the readers have already encountered this study. That's why tell us about your impressions from cardiotocography, how its results were deciphered for you, and what gave you this painless manipulation. Don’t forget to leave feedback and ask questions about CTG, the answers to which most concern you or are still unclear.
Pregnancy is not a disease, however, it is a special period during which the condition of the woman and the little resident in her womb is monitored very closely. And that's great!
Timely tests, examinations and procedures allow you to monitor the course of pregnancy and promptly respond to negative deviations in it. They also allow doctors to prepare for childbirth if there is a possibility that it will be complicated.
Therefore, the expectant mother should not be annoyed if the doctor refers her to another procedure called “cardiotocography”.
Cardiotocography (CTG) is a diagnostic method for assessing the condition of the fetus during pregnancy and childbirth through the frequency of its heartbeat and its fluctuations at rest, activity, during contractions of the uterine muscles, and exposure to external stimuli.
Based on the results of cardiotocography, together with ultrasound, the doctor will be able to timely detect the onset of hypoxia (oxygen starvation) of the fetus, possibly arrhythmia, and identify the causes of this condition.
CTG is prescribed, according to the Order of the Ministry of Health and Social Development of the Russian Federation, starting from the 28th week of pregnancy.
In fact, doctors rarely prescribe this examination before the 32nd week, believing that until this time CTG is not very informative. In total, during the third trimester, during the normal course of pregnancy, the woman will have to undergo two CTG.
If necessary, the doctor can prescribe a CTG procedure as often as he sees fit, even daily.
Indications for additional monitoring of fetal heart rate through CTG analysis are:
- unfavorable result of previous CTG;
- suspected pathology of fetal development;
- or ;
- a decrease in the baby’s physical activity noted by the woman;
- post-term pregnancy;
- the presence of diseases in a pregnant woman such as: diabetes, autoimmune diseases, infectious diseases, etc.;
- blood expectant mother and fetus;
- noted on ultrasound;
- pathological course of previous pregnancies and childbirths;
- entanglement of the fetus with the umbilical cord detected during ultrasound.
This examination method poses no danger either to the pregnant woman or to the unborn newborn baby.
But the information obtained with the help of CTG allows us to identify and reduce the risk of intrauterine suffering in the baby.
How to prepare for the CTG procedure and how to do it?
The CTG procedure is carried out using a special apparatus consisting of an ultrasound sensor and a strain gauge, which are attached to the woman’s abdomen and electronic system heart monitor.
The latter receives data on fetal heartbeats and uterine contractions of a pregnant woman, processes them and displays the result on tape in the form of graphs. How to prepare for CTG during pregnancy?
Cardiotocography does not require additional preparation. The only thing is that before the procedure you can eat something sweet so that the baby moves more actively.
CTG is a completely painless procedure, during which the expectant mother only needs to sit comfortably in a chair or on a couch and not make sudden movements so that the sensors do not slip off the tummy.
Requirements for the patient: remain calm while the cardiotocograph is operating, i.e. for approximately 30-60 minutes. The medical worker and the equipment will do the rest.
First, the midwife or doctor performing the procedure uses a regular ear stethoscope to determine the area on the woman's abdomen in which the fetal heartbeat can be heard most clearly.
At this site, treated with conductive gel, a sensor-electrode is installed and secured with a wide tape-belt, which picks up and amplifies signals about the movement of the fetal heart valves.
Based on the cardiac impulse signals, a graph is drawn showing changes in heart rate throughout the procedure.
At the same time, on the woman’s abdominal wall, just below the navel, in the area of the fundus of the uterus, a pressure sensor (strain gauge) is fixed, which transmits data on the tone of the myometrium (uterine muscles).
The position of the woman during fetal CTG: usually reclining, sitting or lying on her side in a horizontal position, as desired.
Sometimes a situation arises when during the procedure the baby is fast asleep and the woman cannot detect movements. In such a situation, health workers recommend waking up the baby by touching the belly and stroking it. This is absolutely not worth doing.
Additional vibrations are reflected in the recording of the curve, and the device produces false results.
If not a single movement is recorded, you will have to undergo the procedure another day. But this rarely happens, because the baby’s intrauterine sleep is very short and tremors will still be recorded at the beginning of the procedure or at the end.
Determination of CTG, why this type of diagnosis is carried out - you will learn about this from the video.
Types of devices for CTG
Cardiotocography began to gain popularity only in the last twenty years, when data on the condition of the fetus obtained from CTG began to be confirmed by data on the condition of the same babies after birth.
This happened due to improvements in the equipment developed for conducting the survey.
Currently, almost every antenatal clinic and pregnancy clinic, as well as maternity hospitals, are equipped with cardiotocographs.
The most simple CTG devices or fetal (fetal) monitors only provide data on the tape about the fetal heart rate, its motor activity and uterine contractions. Subsequently, the doctor interprets the graphic indicators and draws conclusions about the satisfactory condition of the baby. Such devices, so to speak, of the first level, are practically not used anymore.
Modern devices for CTG examinations, which are most widely in demand by medical institutions, are expert-level devices.
They are distinguished, firstly, by high power, and secondly by the most sensitive sensors and most accurate data display.
In addition, the devices are configured in such a way that the processing of output graph data occurs automatically. The doctor can only prescribe additional examinations or draw up the necessary treatment tactics, if required.
Some CTG machines are equipped with additional options that allow you to assess not only the condition of the fetus, but also the general condition of the pregnant woman: blood pressure, ECG, etc.
Recently, opportunities have emerged for monitoring fetal heart rate remotely. A sensor that picks up signals about the fetal heartbeat via a smartphone connected to the Internet sends data online to the portal, where it is analyzed and sent to the doctor as a result.
Indicator values and norms: interpretation of analysis results
The purpose of the CTG procedure during pregnancy is to obtain quantitative and qualitative values for certain indicators.
CTG norms during pregnancy are as follows:
- Basal fetal heart rate.
Represents the average baby's heart rate. A rate of 110 to 160 beats/min is considered normal.
In case of deviations from the normal basal rhythm, bradycardia is diagnosed if the heart rate is below 110 beats/min. or tachycardia if the heart rate is above 160 beats/min.
With deviations not exceeding 20 beats/min, they speak of a mild form of heart rate disturbances.
More serious deviations indicate the possible presence of an intrauterine infection or entanglement in the umbilical cord.
The cause of abnormal indicators may be the effect of narcotic substances on the mother’s body, fever, or hormonal disorders in the expectant mother.
- Heart rate variability.
Demonstrates the number of deviations of the fetal heart rate from basal rate in 1 minute. A variability of more than 6 per minute is considered a good indicator.
In practice, the amplitude of deviations in the number of heartbeats from the basal level per minute is more often assessed. It's good if it is 6-25 beats.
Low variability (less than 5 per minute), in which the graph resembles a straight line, is characterized as a monotonous rhythm of the fetal heartbeat and, in combination with bradycardia, almost certainly indicates intrauterine fetal suffering from hypoxia, or a disturbance in the functioning of the cardiovascular system.
Maintaining a normal basal level of the fetal heart rate, along with the monotonous rhythm of the heart, may also mean that the fetus is at rest and sleeping.
Increased variability values can also be caused by fetal hypoxia, as well as an effect on its nervous system external irritants, the mother taking any drugs that increase heart rate.
The variability of the basal rhythm of the fetal heart rate on the graph in some cases is reflected as a sinusoidal curve. This picture emerges when the amplitude of deviations in the child’s heart rate rhythm is 5-15 beats/min, if the regularity of such deviations is 2-5 per minute.
The described phenomenon is called “sinusoidal rhythm” and in most cases is associated with severe fetal hypoxia, intrauterine anemia, etc.
- Accelerations
Increased fetal heart rate compared to the basal rhythm.
If within 10 minutes at least two accelerations are detected, more than 15 beats per minute, lasting more than 15 seconds, then this indicator is counted as excellent.
Monotonous accelerations, especially in combination with pronounced tachycardia, give reason to suspect fetal hypoxia.
- Decelerations.
This is a decrease in the fetal heart rate compared to the basal rhythm.
Alarm should be caused by the occurrence of decreases of more than 15 beats/min. for more than 15 seconds.
This does not always indicate pathology and requires consideration of the event in conjunction with the assessment of the episode as well as previous fetal activity.
The detection of obvious decelerations on the CTG graph indicates severe fetal hypoxia, impaired conductivity of the placenta and its functions.
- Number of fetal movements.
During CTG, the indicator of fetal movements is necessarily taken. The moment of movements is noted either by the expectant mother herself, squeezing a special device with her hand, or they are recorded automatically by monitor sensors.
An unfavorable sign is considered if, when an increase in heart rate is recorded, no movements of the baby in the womb are noted. Or, during movements, no response in the form of accelerations was detected.
If under such conditions there is no deterioration in heart function, then the CTG result is interpreted as favorable.
Otherwise, further measures must be taken.
The decoding of CTG is such that each of the indicators is assessed by the doctor on a point scale.
The Fisher scale is most often used to evaluate CTG. Depending on how close to ideal indicators a particular parameter recorded by a CTG sensor is, 0-2 points are given.
The total value of all points demonstrates the assessment of the child’s condition:
- a score from 8 to 10 is considered normal;
- A score of 5-7 points is a reason for repeat CTG and may indicate mild oxygen starvation of the fetus or an unfavorable condition of the placenta.
As a rule, a CTG of 5-7 points may indicate a beginning;
- less than 5 points obtained from CTG results indicate danger intrauterine death fetus, due to hypoxia;
After the first 10 minutes after the start of the examination, a decision may be made to terminate the CTG procedure, with a statement of the satisfactory condition of the fetus.
This conclusion is made with full compliance with the so-called Dawes-Redman criteria by the 10th minute of CTG, namely:
- no decelerations;
- maintaining the basal rhythm within normal limits (120-160 beats/min);
- the amplitude of heart rate deviations from the basal value is not less than 6 and not more than 25 beats/min;
- recording of at least one fetal movement or at least three accelerations;
- noted sporadic heartbeat;
- short-term variability of at least 3 ms.
If after 10 minutes of CTG not all Dawes-Redman criteria are found, then the examination continues until this happens, but not longer than 60 minutes. If this does not happen, then a note is made that the Dawes-Redman criteria are not met and additional examinations are prescribed.
Many pregnant women try to decipher the CTG results on their own before going to the doctor. It is, of course, possible to understand the hardware data, but it is better to entrust the interpretation of the results to an experienced doctor, since the results of the procedure may vary depending on what time of day the pregnant woman underwent the procedure, what medications she is taking, what position the woman was in, etc. .d.
For example, quite often the Dawes-Redman criteria remain unmet by a certain time. But this does not mean that CTG is bad.
An experienced specialist, when deciphering CTG, looks not at the number of points, but at the values of each of the indicators.
Whatever the results of CTG, it is worth remembering that their reliability remains only for several hours. And the very next day the situation may change.
If the result of the examination is unsatisfactory, you should not panic, but prepare for a repeat cardiotocogram, as well as undergo other diagnostic procedures (doplerometry, etc.).
Even the most modern cardiac monitor does not provide a ready-made diagnosis. The final verdict on the condition of the fetus is made by the attending physician, based on the totality of data from all diagnostic methods.
Pregnancy is an exciting event in a woman’s life. This is why it is so important to monitor the condition of the fetus. Cardiotocography is a study that allows you to assess the condition of a child. Only an obstetrician-gynecologist is involved in interpreting CTG, since this requires experience and skill.
Cardiotocography (CTG) – necessary research, with which you can determine the heart rate of the unborn child. This procedure is mandatory. Why is cardiotocography necessary? Sometimes an ultrasound examination does not provide those indicators that allow you to accurately determine the condition of the fetus. With the help of cardiotocography, you can find out whether the baby receives a sufficient amount of air, how he reacts to physical activity, and whether the child can remain healthy after labor.
This diagnosis is extremely important in the third trimester of pregnancy. Most often, the procedure is performed after 30 weeks. A repeat test may be required a few days before your due date. It is during this period of time that false results can be eliminated. The child establishes a sleep schedule. CTG before birth should also be performed.
Cardiotocography also allows you to determine pathologies in the baby’s development, as well as disorders that affect the patient’s health. The CTG procedure is safe for both the baby and the expectant mother.
So, why is cardiotocography needed?
- To determine heart rate.
- To detect pathologies in fetal development: the presence of intrauterine infection, oligohydramnios or polyhydramnios in the mother, disturbances in the functioning of the cardiovascular system.
- To prevent the onset of premature labor.
- To determine the frequency of uterine contractions.
There are special indications for the CTG procedure. Who is recommended to undergo cardiotocography:
- Women who have had an unsuccessful pregnancy experience (premature birth, abortion, frozen fetus, miscarriage)
- Women with negative Rh factor blood, as well as problems with the endocrine system
- Women with diabetes.
- Women who have had complications during pregnancy. These include late toxicosis, oligohydramnios or polyhydramnios.
- During multiple pregnancy.
- If complications and pathologies in fetal development were identified during ultrasound therapy. This is the presence of Down syndrome, size discrepancy, changes in blood flow in the mother's placenta, as well as a decrease in the baby's physical activity.
However, despite the indications, cardiotocography is recommended for all expectant mothers. This will help to detect developing violations and take timely measures to prevent them. Cardiotocography will also give the mother confidence in the child’s health.
CTG procedure
Cardiotocography is done using a special device. This equipment has an ultrasonic effect and the Doppler effect. How is the CTG procedure performed? Before attaching the device to the patient's abdomen, the obstetrician determines the area where the fetal heart rate is most audible. The device sends an ultrasonic signal. This signal is sent directly to the child’s heart area, after which it is reflected and sent back to the device. Based on these data, CTG results are obtained - the number of heartbeats in 60 seconds.
The attending physician must interpret the CTG. It is highly discouraged to make diagnoses on your own. This can lead to panic, the patient will begin to worry and get nervous, which will negatively affect the child’s health.
How long does the procedure take? The duration of the procedure can be very varied. In the normal course of CTG, the procedure takes 15 minutes. If complications arise, it may last longer. The result of cardiotocography is recorded on a special tape. Cardiotocography is performed once a week when the pregnancy is proceeding normally and there are no disturbances in the development of the fetus or mother. If pregnancy occurs with complications, the procedure is performed several times a week.
Survey indicators
To determine the exact condition of the fetus, consultation with your doctor is necessary. What indicators can be a consequence of fetal development disorders? Interpretation of fetal CTG - what CTG indicators are assessed?
- An important indicator when deciphering examination data is the basal rhythm. What is it? Basal heart rate is the average heart rate of a child. The CTG norm of the basal rhythm during baby's sleep is from 110 to 160 beats in 60 seconds. During the baby’s movements – from 140 to 190 heart beats per minute. Deviations of results from the norm may be a sign of the development of fetal hypoxia. Hypoxia is a low oxygen content in the child’s body.
- The next indicator is amplitude. Amplitude, also known as variability, shows changes in heart rate. This indicator is estimated based on the basal rhythm. During the normal course of pregnancy, the amplitude has a constant value, varying from 5 to 25 beats in 60 seconds. Entwining the fetus with the umbilical cord can lead to hypoxia, which will significantly increase the amplitude parameters.
- Increased heart rate, in other words - acceleration, shows an increase in heart rate. It appears in the form of small “teeth” on the graph. The frequency should be no more than 4 times in 15 minutes.
What indicators should not be on the chart? One of the undesirable indicators is deceleration. Deceleration is a decrease in heart rate. This indicator is compared with the basal rhythm. If the baby is in normal condition, deceleration should not be present. However, very slight deviations from the normal rhythm may be tolerated.
There are several types of deceleration:
- Early deceleration (type 1). This type occurs along with contractions. It has both a smooth beginning and an end.
- The second type of deceleration is late. It is characterized by a decrease in the child's heart rate. The occurrence of late deceleration may be a symptom of circulatory problems in the mother's placenta.
- AND last third type – variable. This deceleration is clearly visible on the graph; its “teeth” are directed downward. The cause of the occurrence may be entanglement of the fetus with the umbilical cord, oligohydramnios, as well as excessive movement of the child.
Table of normal and pathological indicators in the fetus is given below:
If the level of certain indicators increases or increases, the fetus may experience hypoxia. Hypoxia is characterized by a reduction in the fetal heartbeat, its deficiency. And with active contractions of the uterus, the baby’s heart rate increases.
How to detect hypoxia:
- Excessively high basal heart rate (more than 180 beats per minute).
- Monotonic basal rate.
- Lack of accelerations.
- Positive result on a stress test.
Other indicators
Other indicators on cardiotocography will help more accurately determine the condition of the fetus. The health of both the child and the expectant mother depends on this. In addition to variability, basal rhythm and accelerations, other indicators are recorded on CTG.
- The norms for fetal health indicators (abbreviation PSP) during pregnancy should be no more than 1.0. If the indicator is 0.8-1.0, the examination must be repeated.
- Indicator from 1.05 to 2.0 CTG - initial violations condition of the fetus. In this case, it is highly recommended to undergo examination after 5 days. Careful monitoring of the fetus's condition is also necessary.
- When the PSP reaches 2.0 to 3.0, the child is on the brink. Urgent hospitalization of the patient is necessary.
- If PSP indicators are above 3.0, it is necessary to carry out premature birth.
The results of cardiotocography are assessed by a doctor using a graph and a special scale - the ten-point Fisher scale. Thanks to this scale, each indicator is assessed with two points. How to decipher CTG using points?
CTG scores according to Fisher:
- If the score is from 1 to 4, the child’s life is in danger. The patient may require urgent hospitalization. The fetus experiences asphyxia.
- A score from 5 to 7 indicates the onset of asphyxia. In this case, it is necessary to urgently consult a specialist. He will help you take appropriate measures.
- When the sum of all points is from 8 to 10, this indicates normal development of the fetus, as well as the absence of pathologies in the development of the baby.
Which CTG during pregnancy is considered bad? If the transcript of the results contains the words “monotonic” or “sinusoidal”, and the basal heart rate is less than 120 beats per minute, this indicates pathologies in the development of the fetus. The examination results are bad. If the tests are bad, you need to undergo a re-examination. It is also imperative to consult with your doctor.
Deciphering CTG by week: indicators may vary depending on the period. It makes no sense to carry out the cardiotocography procedure before the beginning of the third trimester of pregnancy. The results of the study will not be relevant. At 38 weeks of pregnancy, all indicators in the fetus must correspond to the established norm.
During a CTG, the obstetrician can also detect contractions. This phenomenon is absolutely normal. It is explained by the reaction of the uterus to fetal movements. During the procedure, it is necessary to determine whether the child’s heart rate is slowing.
Errors during CTG
Poor results of cardiotocography may not always be the cause of the development of hypoxia. To make an accurate diagnosis, it is necessary to conduct comprehensive studies. Are there errors during the cardiotocography procedure? Of course, every procedure has misfires. There are many recorded cases where, with poor CTG readings, the birth was completely healthy child. However, there were also opposite situations. That is why it is not recommended to worry ahead of time. Stressful situations have an extremely negative impact on the baby's condition.
At bad results The CTG doctor prescribes additional examinations that will help accurately determine whether the baby has hypoxia. A diagnosis cannot be made based on a single cardiotocography procedure.
Why are stress and non-stress tests necessary? A non-stress test is a procedure during which the fetal reaction to movement is examined. A positive non-stress test is extremely dangerous for the child’s health, as it is a sign of the development of asphyxia. This test is also extremely necessary for studying the state of the cardiovascular system.
A stress test is a special type of test in which mild contractions are stimulated. This is necessary in order to determine the physical condition of the fetus. The CTG procedure should only be performed by a qualified specialist. The examination must be comprehensive. This is the only way to make any specific diagnosis.
Interpretation and norm of fetal CTG, these questions concern all expectant mothers. Only the attending physician interprets the results. You should not do this yourself. This could lead to extreme negative consequences. Cardiotocography (CTG) is a necessary study with which you can determine the heart rate of the unborn child. If the level of certain indicators increases or increases, the fetus may experience hypoxia. Cardiotocography is mandatory. Timely diagnosis allows you to identify existing pathologies and take appropriate measures to eliminate them. During a CTG, the obstetrician can also detect contractions. This phenomenon is absolutely normal. Interpretation of CTG results is done only by an obstetrician-gynecologist.
The woman is encountering many tests for the first time; some diagnostic procedures are unfamiliar to her, so they alarm the expectant mother and make her doubt that everything is fine with her and the baby. One gynecologist said that one young woman came to the CTG procedure for the first time, all in tears, with the full conviction that since they ordered an examination, it means they suspected a pathology... I had to reassure the expectant mother with the whole department, explain that this procedure is prescribed to all pregnant women at certain dates and with a specific goal. So what kind of procedure is this - CTG? Why is she prescribed? Let's look at these issues in detail.
1 Why is CTG prescribed?
Cardiotocography (CTG) is a research method that is based on the analysis of the variability of the fetal heart rate (in medical terminology, the fetus is the unborn baby from the eighth week of intrauterine development until birth). Fetal CTG also records the frequency of the baby’s movements and contractile activity of the uterus. CTG is performed using cardiac monitors based on the Doppler principle, which record changes in the intervals between individual cycles of fetal cardiac activity.
By analyzing the results of CTG, you can assess the functional state, frequency of fetal movements, understand whether it is comfortable, whether there is enough oxygen, the frequency and strength of uterine contractions. Thanks to the fetal CTG procedure, the doctor can promptly notice deviations in the course of pregnancy and promptly provide the necessary assistance to the pregnant woman and the unborn baby. Fetal CTG is prescribed both for prophylactic purposes from 30-32 weeks of pregnancy to all women, and for medical reasons (in this case, the timing may be different).
Usually, if the pregnancy is progressing well, a woman undergoes a fetal CTG in the 3rd trimester at least twice, if there are indications (complicated obstetric history, entanglement of the umbilical cord, uterine scars, fetoplacental insufficiency, polyhydramnios or oligohydramnios, features of the development of the fetal cardiovascular system) - more often according to the doctor's indications. During a planned hospitalization several weeks before giving birth, women undergo a fetal CTG every day; this procedure becomes familiar to them, and most look forward to it, because it shows the heartbeat of their baby; some devices reproduce the sound of the baby’s beating heart.
2 How is the procedure done?
Fetal CTG is completely painless for both the expectant mother and her unborn baby. The woman takes a comfortable position, half-sitting or half-lying on her back or side; it is not recommended to carry out the procedure while lying down, because in a lying position, compression of the inferior vena cava may occur and the recording results will be distorted. Two sensors connected to a monitor are attached to the pregnant woman’s belly. One sensor records the fetal heartbeat, and the second - uterine contractions.
Older heart monitors have another fetal movement sensor with a button, it is placed in the woman's hands, and she must press the button every time she feels her baby move. New modern devices do not have such a device. The procedure lasts 30-35 minutes, so before the procedure the woman is advised to get enough sleep and go to the toilet. If the child is not active during the CTG and sleeps in the mother’s stomach, the procedure will not be informative.
To increase the activity of the fetus, a woman in the absence of allergies is recommended to eat one or two slices of chocolate. It is not recommended for a woman to worry, get upset, or worry; these factors can distort the results obtained. The fetal CTG procedure is completely harmless, painless, has no contraindications and side effects both on the maternal and fetal side. Also, a fetal CTG can be performed directly during labor to understand how the baby is feeling.
3 How does a doctor “read” a CTG?
Decoding a fetal CTG is the prerogative of gynecologists, but every woman can have an idea of what the CTG results mean, what the indicators are and whether they are the norm. As a rule, by the 32nd week, the child’s cardiac reflex has already been formed, and for every movement he has a reaction from the cardiovascular system in the form of an increase in heart rate. Sensors record these indicators, which are recorded in the form of a curve on a tape - a cardiotocogram. The gynecologist evaluates the curve on a scale from 1 to 10. Based on this assessment, one can conclude how the child feels in utero, how much oxygen is provided to his body, including the cardiovascular system, and whether there is fetal hypoxia.
4 What parameters does the doctor evaluate?
It is difficult for an untrained person to say what a cardiotocogram means. It shows a continuous line and teeth, directed predominantly upward, less often downward. But how to decipher these indicators? On a fetal cardiotocogram, the doctor evaluates the following indicators:
- The basal rhythm is the arithmetic average of the fetal heart rate over 10 minutes. The normal basal rate is 110-160 beats per minute.
- variability of the basal rhythm (amplitude and frequency). On film, variability stands out in the form of teeth and denticles. Sometimes such jumps frighten a woman, in fact, this is even good. The KTG line should not be straight.
- acceleration is an increase in heart rate by 15 beats or more within 15 seconds. On CTG they look like teeth pointing upward. Occurs when the fetus moves. Normally, accelerations are 2-3 or more in 10 minutes.
- deceleration is a slowing of the heart rate by 15 or more for 15 seconds in response to a contraction or uterine activity. On CTG they look like teeth pointing downwards. If decelerations are rare, shallow, and after them the normal basal rhythm is quickly restored, then there is no reason to worry. The doctor should be alerted to frequent, high-amplitude decreases in heart rate on film.
For each of the four indicators, the doctor awards points from 0 to 2. And then, summing up the result, he receives a final number of points, which gives an assessment of the condition of the fetus and its cardiac activity.
The Fisher rating scale is as follows:
- 8-10 points - normal CTG of the fetus, the child’s condition is good. The expectant mother has no reason to worry.
- 6-7 points - borderline state, which requires repetition of the procedure and reinforcement of the results additional methods research (ultrasound with Doppler sonography).
- 5 points and below - a threatening condition of the fetus. 1-2 points of CTG during pregnancy are critical points, requiring the patient to be hospitalized as soon as possible and decide on further tactics for pregnancy management.
5 Normal results
Normal CTG indicators are a concept that fits into very specific criteria, namely: the basal rhythm should be 119-160 beats per minute, the amplitude of deviation - 7-25 beats per minute, at least 2 accelerations in 10 minutes, absence decelerations or slight decreases in heart rate. These are normal indicators. But you should always remember that a diagnosis cannot be made based on one record, and small deviations from the norm are not a pathology. These schedules may change depending on whether the baby is sleeping or awake, in a calm or active state, and also on what week of pregnancy the examination is performed.
6 Indicators that should alert you
The doctor should be alerted to CTG results that have significant deviations from normal limits: if the basal rhythm is less than 110 or more than 190 beats per minute. A low frequency of 110 or less indicates a slower heartbeat in the fetus, and a high frequency, on the contrary, indicates a pronounced increase in heart rate. Both may indicate fetal hypoxia and oxygen starvation. A basal rate of more than 190 and less than 110 is scored 0 points. It is also not very good when there are no accelerations in response to fetal movement. This may indicate tension and exhaustion of the fetal compensatory reactions and immaturity of the cardiac reflex.
Deep and frequent decelerations always alert the doctor; they may indicate a violation of placental blood flow and require careful study. A monotonously variable basal rhythm or an amplitude of less than 10 or more than 25 beats also raises questions from the doctor. If deciphering the fetal CTG gives a dubious result of 6-7 points, it is necessary to repeat the study and supplement it with other examination methods to determine the reasons that led to this result. But don’t panic right away, this can only harm the condition of the unborn baby.
The reason for immediate hospitalization of a pregnant woman is threatening indicators on the Fisher scale 1 point - 5 points.
7 I wasn’t prescribed a CTG?
You are pregnant, you feel how your baby is growing, kicking, and your meeting with him will take place very soon, but the doctor has not yet prescribed a CTG for you? Why? Perhaps your pregnancy is progressing well, and its term has not approached 32 weeks, there are no indications for more early You don't have. This is only a reason for joy, and not a reason for concern.
8 Is it possible to make a diagnosis using CTG?
No. If any deviations as a result of the procedure are identified, the doctor will refer you to other examinations (laboratory, instrumental). And already in a comprehensive assessment, taking into account the data of all studies, a diagnosis will be made, the results of deciphering the fetal CTG will be confirmed or refuted.
