Cardiotocography is a technique for recording the fetal heartbeat , it is very important for a full assessment of the state of the cardiovascular system and the general condition of the fetus. The CTG method is absolutely harmless, it does not have a negative impact on the child. This technique is used from the 26th week of pregnancy, when the child grows to a sufficient size to fix on his back a sensor of the cardiac monitor through the front abdominal wall. Cardiotocography is indispensable during childbirth, when it is not only necessary to measure the heart rate, but also to determine the intensity of uterine contractions. In our article, we will consider what should the CTG of the fetus be normal?
Indicators of CTG of fetus
The duration of the procedure is about 40-60 minutes, during which the woman is fastened on the stomach sensor, through which the monitor provides information about the heartbeat of the fetus and uterine contractions. The results of CTG of the fetus can be interpreted as follows:
- the basal rhythm index speaks for the average heart rate of the fetus - the basal rhythm frequency is normally in the range of 110-160 beats per minute, and when moving or fighting, 130-190 beats per minute;
- the variability of the heart rhythm of the fetus shows the deviation of the heart rate - in norm the permissible level of deviations should not exceed 5-25 beats per minute;
- desereration or desuleration on CTG is manifested as a slowing of the heartbeat, which appear on the graph in the form of depressions - normally they should be shallow and short;
- Fetal acceleration or an acceleration is an increase in the heart rate, which on the cardiogram is recorded in the form of high teeth - normally should be at least 2 accelerations in 10 minutes;
- the activity of the uterus (tokogram) should not normally exceed 15% of the basal heart rate, the indicator should not exceed 30 seconds.
Fetal CTG - Fetal status indicator
To evaluate the cardiotocogram, a 10-point system is used that describes the criteria described above (basal rhythm frequency, fetal heart rate variability (number of waves and their height), desuleration, acceleration and fetal movement). So, let's consider what number of points the following fetal conditions correspond to:
- satisfactory state corresponds to the CTG of the fetus 9-12 points;
- fetal hypoxia of the middle degree is diagnosed with a total score of 6-8. In such cases, further observation and repetition of CTG is recommended;
- acute fetal distress is exposed at 5 or less points. Poor CTG of the fetus is observed with pronounced oxygen starvation and requires immediate delivery.
Determination of the fetal status index
Modern cardiotocographs are able to automatically calculate the value of the memory bandwidth. Let's consider how to interpret the results:
- the normal state of the fetus corresponds to a PSP from 0.7 to 1.0;
- the initial manifestations of the affected fetus state says the indices of the PSP are 1.01-2.0, in such cases
During the week it is necessary to repeat CTG; - the severe condition of the fetus is diagnosed with a PSP score of 2.01-3.0;
- the critical state of the fetus is confirmed by a PSP of more than 3.0. This condition requires immediate hospitalization in the hospital and the resolution of the issue of operative delivery.
Thus, we examined the features of cardiotocography and methods of interpretation of results. Rhythmic heartbeat in the fetus with a reduction frequency of 110-160 beats per minute indicates that the baby is okay.