However, the main parameter used to diagnose the state of the heart system is the heart rate (heart rate). At the same time, this parameter changes and completely depends on the period at which diagnostics are carried out.
What are the HR norms in the early stages?
To determine the deviations, when analyzing the work of the cardiovascular system of an unborn baby, a table is used in which the norm of the fetal heart rate is prescribed for weeks. Particular attention is paid to the time in which this diagnosis is carried out. This is explained by the fact that this parameter changes so quickly that at the end and at the beginning of one week different values can be fixed. For example, at the beginning of week 7, the heart rate is 126 beats per minute, and at the end is 149. By the 13th week the heart rate is on average 159 beats.
How does the heart rate change in the 2nd and 3rd trimesters?
The heart rate, changed by the weeks of pregnancy, undergoes changes in the 2nd trimester. So from 12 to 14 weeks for the norm taken indicators of 140-160 beats per minute. Such a heartbeat is observed right up to the birth process. The deviation in this or the opposite direction, most often indicates the presence of a violation. At the same time, the main cause of heart rate changes at any gestation period is fetal hypoxia. Most often, it leads to an increase in heart rate, tachycardia. In severe cases of oxygen starvation, a bradycardia occurs, which is a consequence of the so-called fetoplacental insufficiency. In such situations, the doctor decides what to do next: to perform premature births (if possible and allow the term) or to observe the woman, trying to stabilize her condition.
How is the heart rate assessed late?
The assessment of the rate of heart rate, which is carried out for weeks of pregnancy, is carried out later with the help of CTG. Begin it with 32 weeks, and repeat this procedure every 14 days. Together with the fixation of the heart rate, fixation of uterine contractions as well as motor activity of the baby occurs. It is these indicators that are taken into account when assessing the general condition of the fetus, as well as in assessing intrauterine development.
What causes a change in the fetal heart rate?
There are a lot of reasons for increasing the fetal heart rate. This fact complicates the process of diagnosis, and sometimes it is not possible to establish the one that led to the development of the violation. However, not always the change in this indicator is a consequence of the existing violation. So, to the deviation of heart rate from the norm can result:
- chronic diseases of the pregnant;
- deterioration of the psycho-emotional state of the pregnant woman;
- increased physical activity.
In addition to the above factors, the increase in fetal heart rate is promoted by excessive motor activity of the pregnant woman. So, during wakefulness this indicator slightly increases, and during rest the heart of the baby beats less often. These factors are also taken into account in the diagnosis.
Thus, such a characteristic of the functioning of the cardiac system of a baby in the womb is quite informative and is used for the timely diagnosis of diseases. In most cases, it is due to a change in this parameter that doctors set the fetal hypoxia, which requires correction, since Later this negatively affects the fetal development of the fetus.