KTG – what is it and when to do it? How is CTG performed?

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KTG is one of the most important tests performed in pregnant women. Every mother wants to know if the baby she carries in her belly is developing properly. One of the elements of the fetus’s well-being is the work of its heart. Its assessment can be made thanks to CTG (cardiotocography) examination.

KTG (cardiotocography) consists of cardiography, which continuously records the activity of the fetal heart and tocography, i.e. registration of uterine contractions. The test is performed when there is a suspicion of tachycardia, arthymia and fetal bradycardia or in women at risk of pregnancy. If the baby is developing properly, KTG is done at the end of pregnancy and during labor.

Thanks to CTG, you can monitor your baby’s heart rate. This enables the doctor to react suddenly in the event of a threat to the life of the fetus. It is important to know that a baby must pass through a tight birth canal during birth. It is an activity that requires a lot of effort from him. The procedure significantly contributed to reducing the number of deaths of newborns around the world.

KTG is one of the major obstetric tests. This is one of the most effective tools for examining a child’s health. When the frequency of the strokes is low, it can be a harbinger of hypoxia in the child’s body. On the other hand, when the baby’s heart beats quickly, it may be a signal that there is an intrauterine infection. Nearly every pregnant woman undergoes CTG.

Find out what the symptoms of labor are

KTG is usually performed after the 25th week of pregnancywhen your expected delivery date is approaching. Then, the examination should be repeated, if indicated, to be delivered, or in the case of postpartum pregnancy (usually every 2-3 days). The doctor may order CTG, but it is not mandatory. The prerequisites for performing CTG are:

  1. uterine contractions;
  2. missed delivery by at least 1 week;
  3. not feeling the baby’s movements;
  4. suspected fetal bradycardia, tachycardia or arrhythmia,
  5. birth.

The test is indicated when a pregnant woman also develops abdominal injuries, diabetes or vaginal bleeding. However, the doctor may recommend CTG in any situation in which there is any risk to the pregnancy. Cardiotocography, like other pregnancy tests, is free of charge, as long as the pregnant woman is insured with the National Health Fund.

The test is performed in two ways. These are:

  1. external monitoring – this method is used most often. It involves wearing belts with built-in sensors on the belly of a pregnant woman. While performing this CTG test, one of the sensors registers the baby’s heartbeat; the other measures the duration and strength of uterine contractions. The belts are connected to a device on which the doctor reads the value of the measurements. During the CTG examination, the woman lies on her left side.
  2. internal monitoring – this type of CTG examination is recommended when the child’s life is at risk. An electrode is inserted from the side of the cervix and placed next to the baby’s head. The procedure is possible only when the membranes are ruptured and the dilation is at least 2 cm. To test for uterine contraction, a catheter must be placed on the abdomen or uterus – therefore internal monitoring is an invasive type of CTG and carries some risk of infection.

No special preparations are needed to perform the CTG test. A cardiographic head is attached to the woman’s abdomen, in the place where the baby’s heart sounds best. The device attaches to the elastic abdominal belt. Above it is placed a tocograph head responsible for recording uterine contractions.

The tocographic and cardiographic heads are connected to the CTG apparatus. The test result is obtained in the form of cardiographic and tocographic charts. When performing CTG, it is possible to observe the baby’s movements – in some cases, doctors recommend that a woman signal any movement she feels. It uses a special button built into the monitoring device.

Find out what labor contractions are

As standard, the procedure takes 20-30 minutes. KTG examination should always be interpreted and described by a doctor. In some cases, the test may take up to an hour – this usually happens when the result is worrying.

Moreover, in extreme situations, the patient is connected to the apparatus for the entire duration of the delivery. KTG examination is completely safe for health – it does not pose a threat to either the baby or the mother.

In some cases, the physician may decide to perform CTG testing after the administration of pregnant oxytocin. This method is called the oxytocin test. It is recommended for women who have had complications during a previous pregnancy or their current pregnancy is at risk. Thanks to oxytocin, it is possible to check the efficiency of the placenta during contraction.

KTG examination – concepts that are worth knowing

Before visiting a doctor, it is worth knowing a few professional terms, which you will certainly hear about sooner or later during the CTG examination. These are i.a. baseline or baseline fetal heart rate; oscillation, or fluctuations in the heart rate of the fetus; decelerations – short-term slowdowns of the fetal heart rate; early deceleration – slowing the child’s heart rate.

Such concepts also include:

  1. acceleration – a short-term increase in heart rate. When they occur during CTG testing, they mean that the baby is properly oxygenated. Accelerations should appear when the baby is moving. They are also visible during contact with the fetus (eg when touching it through the vagina or touching the abdomen. When the baby’s heart beats normal, the acceleration lasts no less than 15 seconds to accelerate the heart rate.
  2. early decelerations – their occurrence depends on uterine contractions. Early decelerations begin with the onset of uterine contractions. The cause of its formation is mild hypoxia. In some situations they mean that the baby’s head is under pressure. Thanks to the CTG examination, they can be detected faster. The presence of early deceleration does not mean that there are difficulties in delivery.
  3. Late decelerations – when it turns out that there are late decelerations during the CTG procedure, it is a sign that the child has limited access to oxygen for some reason. In some cases, the cause is due to maternal illness or too much uterine contraction. This is sometimes a symptom of a premature detachment of the placenta. The phenomenon of late decelerations always means that the child is hypoxic.
  4. tachycardia – is a disturbance of the heart rhythm that manifests itself in the form of rapid beating, although it is not caused by excessive exercise. Its another name for tachycardia. Thanks to the CTG examination, it is possible to detect the disease early enough. The doctor’s failure to respond to alarm signals about the presence of the disease may lead to permanent impairment of the child and even death.

CTG examination enables the registration of the child’s heartbeat and all its movements. The appearance of acceleration in the 20-30 minute record often accompanies the fetal movements or sounds coming from the outside (the so-called acoustic test) and indicates the child’s well-being – it is the so-called reactive test. The heart rate of the baby in the mother’s womb should be in the range of 110-160 beats per minute.

  1. Know the norms of the fetal heart rate

The purpose of the CTG test is to show how the baby’s heart works. It is worth mentioning that a child’s heart rate range may change from time to time, but these fluctuations should only be for a short time. The lack of acceleration and the constriction of oscillations may mean that the baby is hypoxic. The oscillation is usually between 5 and 25 beats per minute, but is dependent e.g. on whether the baby is asleep or not.

  1. Find out more about heart defects in children

Correct reading of this parameter is one of the most important “messages” that the child sends. If the fetal heartbeat is normal, then the little man is developing properly. Conversely, when it is too large or too small, it may suggest that one of the pathological processes is developing. Interestingly, the fetal heart rate is greater than that of adults, ranging from 110 to 150.

When the baby’s heart rate is too high, i.e. above 160 beats per minute, it is a symptom of tachycardia. Its causes are, among others, intrauterine infection or lack of proper oxygenation. A baby’s high heart rate can also be a reaction to the severe stress that the mother is experiencing or to anemia or infection.

Conversely, a fetal heart rate that is too low, i.e. less than 110 beats per minute, is a symptom of bradycardia. These conditions are caused by reasons other than the aforementioned tachycardia. A low fetal heart rate can be caused, for example, by the umbilical cord wrapping around the baby’s neck, hypoglycaemia or too low blood pressure in the mother. Placental insufficiency and uterine contractions can also be another cause.

Find out what the heart rate norms are

The CTG record, which proves that a child is in good condition, is almost always reliable. On the other hand, the results that indicate that the health of the fetus is at risk is sometimes a false alarm.

It often happens that the expectant mother takes a position during the examination, in which her vena cava or fetal umbilical cord is compressed – after changing the position of the body, the CTG result immediately improves.

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