There are two methods of performing CTG of the fetus during pregnancy - external and internal examination.
With external CTG on the stomach of a pregnant woman, an ultrasound sensor is installed, which fixes the rhythm of the heart rate and the heart rate. This method is widely used both during pregnancy and, directly, with labor. Internal, or direct CTG, measures the tone of the uterus and intrauterine pressure during labor. A tensometric sensor is used, which is attached to the head of the fetus during childbirth.
The results of the study are output by the device in the form of a graphic image on a long paper tape. In this case, the contraction of the uterus and the movement of the crumbs is output as a curve in the lower part of the tape.
When do CTG fetus?
As a rule, not earlier than 28 weeks. The most informative is cardiotocography from the 32nd week. It is from this time the child can already be active for 20-30 minutes.
Therefore, in the third trimester, with normal indicators, a pregnant woman must undergo KTG at least two times. The test is performed on an empty stomach or a few hours after eating. On the eve it is desirable to try to have a good rest. During the KGG, a pregnant woman sits or lies on her side. On average, the procedure does not last more than 30-40 minutes, and in some cases, 15-20 minutes is enough.
Norm of results of CTG of fetus
After the passage of the study is very difficult to understand the results. What does the fetal CTG show?
As a result of the study, the doctor receives the following data: basal rhythm of heart rate or, heart rate (normal - 110-160 beats per minute at rest and 130-180 - in active stage); tokogram or uterine activity; Variability of rhythm (the average height of deviations from the heart rate can be from 2-20 strokes); Acceleration - acceleration of heart rate (within 10 minutes from two or more); Deceleration - a slowdown in heart rate (shallow or absent).
Further, according to the method of Fisher, for each result obtained, up to 2 points are added, which are further summarized.
If you have 8-10 points, there is no reason to worry. These indicators of CTG of the fetus are considered the norm.
6-7 points indicate the presence of certain problems that should be immediately identified. A woman will need additional research.
5 and fewer points - this is a serious threat to the life of the fetus. The baby most likely suffers from hypoxia (oxygen starvation). You may need urgent hospitalization. And in some cases - premature birth.
Is CTG harmful to the fetus?
Many future parents are mistrustful of cardiotocography. It should be said that such fears are completely vain. This study provides a lot of useful information without harm to the health of the mother or fetus.
And no matter what results you get with the first study, do not panic immediately. After all, CTG is not a diagnosis. A complete picture of the condition of the fetus can not be given by one method. It is important to have a comprehensive study - ultrasound, doppler, etc.
And at the same time, the significance of this research is undeniable. CTG provides data on the fetal status during pregnancy. Also, in the process of labor, it is possible to give a timely and correct assessment of the birth and condition of the fetus.