CTG during pregnancy: transcript

2024 Author: Priscilla Miln | [email protected]. Last modified: 2024-01-15 22:35

The longer the pregnancy, the more often women have to visit the clinic. Examinations, analyzes, examinations - from all this, at the end of the term, the head begins to spin. However, all this is necessary to control the condition of the fetus and the woman as well. Therefore, in the third trimester, a procedure such as cardiotocography (CTG) is provided. During pregnancy, it allows you to find out the heart rate of the baby and not only.

Term

Cardiotocography, also known as CTG, is a continuous synchronous recording of the fetal heart rate and uterine tone. The data obtained as a result of CTG are presented in the form of graphic images on a special tape. Since the device simultaneously registers two readings, the result on the calibration tape is displayed in two graphs.

In addition to these two indicators, the cardiotocograph can also track fetal activity during the recording of heart rate. During your workthe device receives data using two sensors: ultrasonic and strain gauge. The general principle of the fetal monitor is based on the Doppler effect.

The essence of the research method

Due to the greatest availability of the study of fetal cardiac activity in the womb, it became one of the first indicators of assessing its vital activity. At first, the heart rate was listened to by simply putting an ear to the mother's abdomen. Later, a stethoscope was used for these purposes. It was only at the end of the 1960s that cardiotocography entered clinical practice.

CTG during pregnancy, both then and now, is recorded using two sensors that are attached to the mother's abdomen. One of them records the frequency of contractions of the heart muscle of the child, the other - the contraction of the uterine walls of the mother. In addition, the device captures the movements of the baby. This is necessary to find out the reaction of the fetus to uterine contractions.

Types of CTG

Cardiotocography is a really necessary type of research not only in the last stages of pregnancy, but also during childbirth. It comes in two forms, but women tend to only experience one of them.

Types of CTG:

• outer;
• internal.

External CTG during pregnancy is used when the integrity of the fetal bladder is not broken. In this procedure, both sensors are attached to the woman's abdomen in places where the signal is best received. As a rule, the strain gauge is applied in the region of the uterine fundus, andultrasound - at the point of stable heart rate reception (depending on the location of the child).

Internal cardiotocography is usually used during childbirth when the amniotic sac has burst. In this case, the general principle of how CTG is done during pregnancy changes dramatically. Instead of sensors for recording heart rate and uterine tone, an electrode and a catheter are used. The electrode is applied directly to the baby's head, and the catheter is inserted into the uterine cavity. It is worth noting that this type of cardiotocography is not very common, so the only study that a woman should prepare for is external CTG during pregnancy.

Indicators

To analyze the condition of the fetus, the doctor must evaluate several indicators at once, which are recorded by the fetal monitor. For a person without a medical education, the numbers recorded on the printout of the device are unlikely to say anything. To at least approximately understand the result of the study, you need to at least know the norms of CTG during pregnancy.

Indicators for CTG analysis:

• Average heart rate.
• Myocardial reflex.
• Variability.
• Periodic fluctuations in heart rate.

All these indicators, which shows CTG during pregnancy, relate directly to the work of the fetal heart muscle. The doctor also looks at the tokogram, which characterizes uterine activity.

Main indications for CTG

The first and main indication for CTG during pregnancy is timing. Cardiotocographyis assigned to absolutely all pregnant women registered in a he althcare institution, whose gestational age has reached 30-32 weeks of pregnancy. However, for some, it may be assigned earlier. The main indications for this are:

• Negative Rh factor in the blood of a pregnant woman, which can cause the development of hemolytic disease of the newborn.
• Presence in the patient's record of information about spontaneous or medical abortions, premature births.
• Complaints of a pregnant woman about a decrease in fetal activity.
• Complications or pathologies of pregnancy (toxicosis, polyhydramnios, etc.)
• Fetal abnormalities detected by ultrasound.
• Endocrine and systemic diseases.
• Expiration of the estimated delivery date (postterm pregnancy).

In the absence of indications, CTG is usually not prescribed before 32 weeks of pregnancy. After this period, the woman will undergo examinations at each scheduled visit to the local gynecologist.

Deciphering CTG during pregnancy

The doctor deals with the decoding of CTG. However, some gynecologists are so laconic that women try to do it themselves. In fact, a pregnant woman has every right to know about her state of he alth, so you should not be shy about being interested in deciphering CTG. During pregnancy, it is very important to clearly understand the possible risks that may arise during childbirth.

After spending some time under the sensors, the woman getsa printout with the graphs that the device compiled. According to these graphs, the state of the fetus is analyzed based on:

• Basal rhythm. The norm at rest is 110-160 bpm, with active fetal movement - 140-190 bpm.
• Variability - 5-25 bpm
• Acceleration (increased heart rate) - 2-3 times in 15 minutes.
• Decelerations (decrease in heart rate) - normally, slowing of the heart rate should be absent or be insignificant in depth and duration.

CTG norms during pregnancy allow you to display the result of the study in points, where:

• 0-5 points - fetal hypoxia, urgent need for hospitalization.
• 6-7 points are the first signs of oxygen starvation.
• 8-10 points - all indicators are normal, there are no deviations.

Scoring table

To calculate the scores, doctors use a special table. It contains normalized indicators, which shows CTG during pregnancy, and the number of points for each of them.

Table:

Indicator	0 points	1 point	2 points
Basal Rhythm	< 100; 180.	110-119; 161-179.	120-160
Number of oscillations (number of heart rate changes)	Under 3	3 to 6	More 6
Frequency amplitude	5 or sinusoidal graph	5-9 or more 25	10-25
Accelerations	No	Periodic	Sporadic
Decelerations	Late continuous or variable	Early (severe) or variable (mild, moderate)	None or early (mild, moderate)

What diseases can be detected by CTG?

To understand how important this research method is, you need to find out what CTG shows during pregnancy. The results of cardiotocography reveal a number of fetal pathologies. Moreover, some of them can cause urgent hospitalization of a pregnant woman.

With the help of CTG, you can identify:

• oxygen starvation (hypoxia);
• presence of intrauterine infection;
• lack or, conversely, excess amniotic fluid;
• fetoplacental insufficiency;
• developmental disorders of the cardiovascular system, etc.

Due to the abundance of pathologies that can be detected using cardiotocography, women are prescribed CTG during pregnancy. At week 34, the deadline for the initial passage of this procedure, so in the third trimester you should not miss planned visits to the doctor. Otherwise, you can miss a serious illness that cancause fetal death.

CTG during pregnancy: how long does the procedure take?

On average, recording a cardiotocogram lasts about 30-40 minutes. However, this process can increase significantly if the first write resulted in bad data. If the CTG indicators are far from normal, this does not mean that there are any pathologies. Maybe the baby is just sleeping. Therefore, before the procedure, you need to prepare and bring the baby into an active state.

In order to wake up the baby, you need to visit the pool or just walk 1 hour before the appointment. Also, do not go for cardiotocography on an empty stomach. If we talk about how CTG is done during pregnancy with respect to the time of day, then the intervals from 9 am to 2 pm are optimal. As a rule, it is at this time that the fetus is at its peak of activity.

If the child overslept during the recording, the procedure will have to be repeated. Therefore, instead of 30 minutes, it may take up to 2 hours to record a CTG.

Is there any harm from this procedure?

Cardiotocography, just like ultrasound, has no contraindications. Therefore, this procedure is completely safe for both the fetus and the mother. Usually CTG is recorded in the third trimester 2-3 times a month. But if there is evidence, the study can be carried out much more often, which causes concern for women.

Such fears are groundless. CTG is a very informative type of medical examination. It allows you to identify pathologies of pregnancy in the early stages and taketimely measures to eliminate them. Therefore, refusing cardiotocography due to prejudice, a woman endangers the he alth of her child.

Reliability of CTG results

Unfortunately, sometimes there are cases when doctors make an erroneous assessment of the results of CTG. Most often this happens due to the inexperience of a specialist who could not correctly assess the totality of indicators. However, medical error is not the only reason why there is room for error in medical research.

In obstetric practice, cases are mentioned when, in the presence of oxygen starvation, the fetus adapts to it. Therefore, when recording CTG, pathologies of this condition may not be detected. The same phenomenon can be observed if there is a normal amount of oxygen in the bloodstream, but the tissues are not able to adequately receive and apply it, resulting in fetal hypoxia.

However, CTG is not the only research method. If there are doubts about the patient's diagnosis, additional procedures are prescribed for him. Only based on a comprehensive examination, doctors can make a correct diagnosis and conduct timely treatment. Therefore, you should not immediately worry about poor indicators of cardiotocography. As a rule, if a woman has been absolutely he althy throughout the entire pregnancy, an experienced doctor will give her a little time to “stir up” the baby and overwrite the result.