From what week do CTG? Deciphering CTG during pregnancy

2024 Author: Priscilla Miln | [email protected]. Last modified: 2023-12-16 00:21

A simple and informative way to assess the condition of the child during the third trimester of gestation, in the first (during labor) and second (during attempts) periods of labor is to monitor the heart activity and contractions of the mother's uterus. Since what week do CTG? The study can be carried out from the twenty-eighth week, but often the most accurate indicators can only be obtained from the thirty-second week. This is an effective and safe diagnostic method that has no contraindications, so expectant mothers do not have to worry about their he alth or the well-being of their baby.

What is cardiotocography

Why do CTG for pregnant women? Cardiotocography is a painless, simple and effective method for studying the frequency of contractions of the fetal heart and the contraction of the walls of the mother's uterus. The indicators are recorded by special sensors, pass through the apparatus and are applied to a paper tape orare reflected on the monitor. Deciphering the results allows the doctor to assess the child's condition in several ways. Therefore, expectant mothers are often interested in when they do the first CTG. It is worth noting that the diagnostic method is used exclusively in the third trimester, because it is impossible to obtain a high-quality record earlier.

CTG allows you to identify a number of anomalies, although there are more advanced methods for diagnosing a child's condition. With the help of cardiotocography in late pregnancy and during childbirth, it is possible to identify heart disease, foci of infection or inflammation, anemia, impaired blood flow, entanglement of the umbilical cord, the presence of a knot on the umbilical cord, determine the degree of impact of mother's diseases on the child's condition and the effectiveness of certain medications.

Some of the pathologies listed above can lead to intrauterine death of the fetus or disability of the child. Oxygen deficiency, for example, can cause cerebral palsy, gastrointestinal dysfunction, hypertension, kidney failure, seizures, seizures, and so on. In some cases, the correction of the identified anomalies can be carried out even during pregnancy. CTG also helps to make the best decision (that is, safe for mother and child) about the method of delivery.

When CTG is done during pregnancy

Cardiotocography is a safe way to assess the condition of the fetus, so the procedure is prescribed for many pregnant women. Since what week do CTG? Registration is made in the third trimester. You can do CTG already with28-30th week of pregnancy, but even at these times it is still possible not to get reliable results. The final formation of the cycle, when the period of motor activity of the fetus is regularly replaced by rest, occurs only from the thirty-second week of pregnancy. When diagnosing and evaluating the results, it is also worth considering that the duration of the fetus's sleep is an average of thirty minutes.

At what time do they start doing CTG for pregnant women? In the normal course of pregnancy, the first procedure can be prescribed at about thirty-two weeks. Starting from this period, CTG is carried out no more than once a week. The usual frequency is once every ten days. In the presence of pregnancy complications, but favorable previous results, the study is carried out every five to seven days, as well as changes in the woman's well-being. With hypoxia, CTG is done daily or every other day until the child's condition returns to normal or until a decision is made on early delivery.

Optimal time of day

The optimal time for recording is the period of fetal biophysical activity, that is, the interval between 9 and 14 hours, and also between 19 and 24 hours. Diagnosis is carried out on an empty stomach or two hours after a meal, during or within an hour after the administration of glucose. If the time is not observed for any reason and deviations from the norm are determined, then a re-recording must be carried out in compliance with all the rules. This is due to the fact that the child's body is completely dependent on the mother. In addition, to influence the motorFetal activity and ability to respond to stimuli can affect a woman's blood sugar.

CTG during labor

From what week do CTG? As mentioned above, cardiotocography is prescribed for approximately thirty-two weeks. But in some cases, the control of fetal heart rate and uterine contractions is carried out for the first time only in the first stage of labor. If the pregnancy is uncomplicated, then listening to the fetal heartbeat with a conventional obstetric stethoscope may be enough before that. This is a wooden tube that the doctor puts on the belly of the expectant mother at every appointment.

In a normal birth, the baby usually has enough room to overcome the difficulties that arise in the process, but there may be a violation of the supply of oxygen, which leads to hypoxia. This condition is dangerous because it can lead to irreversible reactions. Therefore, CTG is mandatory during childbirth. In the first period, there are enough records every three hours. The second period of labor is sometimes generally recommended to be carried out under the continuous control of the CTG apparatus. If indicated, the frequency of the study is determined by the doctor on an individual basis.

In many domestic hospitals, three examinations on the CTG machine are considered mandatory: upon admission to the maternity ward with contractions, immediately after the amniotic fluid is discharged and before the onset of attempts. If indicated, monitoring is carried out more frequently. The study presents some inconvenience for a woman, because it is difficult to remain still during contractions, but sometimes CTG is indispensable. This procedure is especially important when using epidural anesthesia, chronic fetal hypoxia, weakness of labor, post-term pregnancy, gestosis and some other complications.

Indicators for regular recording

From about the 31st week, CTG is performed once a week, if no suspicious indicators were detected during the first procedure. But there are cases that require constant monitoring. Indications for regular recording are multiple or postterm pregnancy, prolonged exposure to infection on the body of the expectant mother, diabetes mellitus, polyhydramnios or oligohydramnios, chronic diseases in women, hemolytic disease (incompatibility of mother and child by blood group or Rh factor), the presence of a scar on the uterus, bad habits, gestosis in combination with convulsions and high blood pressure, miscarriages or abortions in history, spotting, prolapse of the umbilical cord or entanglement around the neck of the fetus. In childbirth, constant monitoring is indicated for weak labor activity, the appointment of labor stimulation, the introduction of epidural anesthesia, chronic fetal hypoxia, post-term or premature pregnancy, multiple pregnancy, late toxicosis.

How the study is done

CTG on the 37th week, later or earlier, is carried out according to the same algorithm. In the treatment room, the expectant mother will be offered to lie down on the couch. The semi-sitting position is preferred, but some patients prefer to lie on their left side. The nurse will attach special sensors to the abdomen, which are fixed with straps. The upper one will fix the tone of the uterus, and the lower- Fetal heart rate. The conductive gel lubricates only the second sensor. Then the recording process takes place. The results are transferred to paper tape.

Some CTG machines are not equipped with an automatic fetal movement recorder, so the doctor may ask the patient to pick up a special remote control and press the button when the baby is active. If the indicators are favorable, the study usually lasts no more than 15-20 minutes. Often, the diagnosis takes from 45 to 90 minutes, because it can fall during the child's sleep period. It is important to remember that the results of the study may be affected by the emotional state of the expectant mother, stress, poor nutrition or exposure to weather conditions.

CTG indicators: normal

Deciphering CTG is necessarily carried out by a doctor, but you can figure out the results yourself. During the study, the fetal heart rate, basal heart rate (contractions of the heart muscle that persist for ten minutes and in the intervals between contractions), changes in basal heart rate, slowing or accelerating heart rate for 15 seconds or more are evaluated. Normally, CTG at 30 weeks and at another time should show the following results: basal rhythm - from 120 to 160 beats per minute, amplitude of the basal rhythm - 5-25 beats per minute, no slowdown in heart rate by 15 or more beats per minute for 15 seconds or more, two or more short-term accelerations of heart rate during ten minutes of recording.

CTG transcript: what do the scores mean?

To simplify the interpretation of diagnostic results, it is proposedscoring system. What do CTG scores mean? The normal state of the fetus is 8-10 points. A score of 5-7 points indicates the initial signs of oxygen deficiency. In this case, you need to repeat the recording within a day. If the result does not change, then additional research methods are needed: dopplerometry, assessment of the fetal condition by ultrasound. A score of 4 points or less indicates serious changes in the child's condition. An immediate decision must be made on emergency delivery or intensive care until the indicators return to normal.

Zero points are given for basal heart rate if the rate is less than 100 beats per minute or more than 180, one point - with a heart rate of 100-120, 160-180, two points - 120-160. If there are no accelerations of heart contractions during fetal movement, then zero points are given for this indicator, in the presence of periodic accelerations - one point, with acceleration on each movement - two points. In the absence of a slowdown in the heart rate, two points are given, with short-term slowdowns - one point, with long-term slowdowns - zero points. In the same way, heart rate variability and amplitude are estimated from the table.

Heart rate assessment

What defines CTG? During the diagnostic procedure, the condition of the fetus is assessed by heart rate, contraction variability, slowing or accelerating the heart rate. The rhythm of contractions of the heart muscle should normally be 110-160 beats per minute. The minimum and maximum indicators in this case are not of interest to the doctor, the average values are important here. To on my ownto interpret the results, you need to move the printed paper tape to arm's length and imagine or draw a straight line along the graph with your finger. The level on the vertical axis will be the middle beat.

Heart rate variability

There are many small teeth and a few large ones on the curves of the CTG graph. Small ones show deviations from the rhythm. Normally, there should be no more than six of them per minute, but it is not so easy to calculate the exact number, so doctors often evaluate the amplitude of deviations - average changes in height, which normally amount to no more than 11-25 beats per minute. If the change in altitude is 0-10 beats in the same amount of time, then this may indicate deviations. But such an indicator is normal if the baby is sleeping or the gestational age does not exceed twenty-eight weeks of weeks. If the measured value rises to 25 beats per minute or more, then the doctor may suspect hypoxia or entanglement of the umbilical cord around the neck.

Assessing increases and decreases

When evaluating slowdowns and speedups, the doctor draws attention to the large teeth on the CTG chart. When a child is active, his heart beats faster. On the graph, this is reflected in the form of a large tooth directed upwards. In ten minutes of research, there should normally be no more than two such increases. With CTG, increases may not be detected. You should not panic, because the child can just sleep during the diagnosis. Slowdowns are the big teeth on the graph that point down. High-amplitude decreases can alert the doctor, but the result should be evaluated together withthe second chart, which records uterine contractions.

Incorrect study figures

From what week do CTG to get the most reliable results? Diagnosis can be carried out from the twenty-eighth week of pregnancy, but the exact indicators, most likely, can only be fixed closer to 32 weeks. But even at this time, the results can be greatly distorted under the influence of certain factors. The indicators may be affected by excessive activity of the child or a period of rest, insufficient conductive gel on the sensor, high BMI of the mother (extra pounds), eating a large meal immediately before the study. The results may be unreliable in multiple pregnancies. Sometimes the condition of the future mother and fetus is affected by adverse weather conditions, emotional mood or previous stress.

Is CTG harmful during pregnancy

Cardiotocography is a completely safe procedure for which there are no contraindications. The method does not cause any harm to either the mother or the child. If necessary, the recording can be repeated for a long time and even daily. This survey provides sufficient information and helps to identify possible violations and threats in time, as well as to take the necessary actions in a timely manner. The results obtained should be considered in conjunction with data on the general nature of the course of pregnancy and in connection with the indications of other studies, in particular Doppler and ultrasound.

It is important to remember that the results of CTG are not a final diagnosis, but only one of the ways to assess the child's condition. In childbirth, for example, the nature of the record will alarm the doctor in case of a short-term violation of blood flow in the vessels due to compression of the umbilical cord by the baby's head. But it doesn't harm the fetus. Rarely, but doctors are faced with the opposite situation: CTG does not cause concern with long-term hypoxia. This can happen if the fetus has a reduced need for oxygen as a result of a defensive reaction. The condition of the child is unsatisfactory. In this regard, in case of any deviations, additional diagnostic procedures and tests may be carried out.