During the ultrasound examination, the doctor maintains a special protocol. In it, he brings all the information about the growth and development of the baby. One of the most important indicators of the protocol is the biparietal size of the head. In this article, we will talk about what fetal BDP is by week and why you need to know about it during pregnancy.
Indicator value
The brain is the most important human organ. The proper development of the fetus directly depends on the state of the baby’s brain. During the ultrasound, the doctor pays special attention to the study of the child’s head, calculates the fetal BDP by week. This determines how well the fetus develops. Biparietal size is the distance from the temple to the child’s temple, measured along the minor axis. That is a kind of "width" of the head. Another important indicator of ultrasound is the distance from the forehead to the back of the head along the major axis (LZR). But biparietal size is crucial during pregnancy. Accurately enough, it is installed on a period of 12 to 28 weeks. In addition to the fact that the BDP of the fetal head indicates the correct intrauterine development of the baby, it indicates the possibility of physiological birth. In case of serious deviations, the issue of labor by caesarean section may arise.
Biparietal size - norms of indications
To make it easier for the doctor to navigate in terms of norm and pathology, special tables have been developed. They show average rates of biparietal size using percentiles. These are medical statistics, which indicate the upper (95 ave.) And lower bounds (5 ave.), As well as average indicators (50 ave.). How to determine the norm of fetal BDP by week? The table represents percentiles. The doctor finds the 50th value and looks at the boundaries of the extreme readings. For example, at 12 weeks, the rate of BDP is 21 mm. Furthermore, permissible deviations are 18-24 mm. Therefore, mother should not worry if she sees in the protocol, for example, the value of BDP 21 or 22. The main thing is that they are less than the upper limit.
Danger of deviations
Sometimes the doctor sees that the fetal BDP indices by week are not within acceptable limits. What can it talk about? To begin with, the specialist evaluates other fetal indicators (abdominal circumference, thigh length, etc.). If all indicators go beyond the norm, this may indicate a large fruit or spasmodic growth. In the second case, with repeated ultrasound in a couple of weeks, the numbers are likely to align. If the parameters of the BDP of the fetal head are significantly higher than normal, this can indicate serious health problems for the baby. An increased size occurs with brain tumors or other malignant formations, cerebral hernia, hydrocephalus. In the latter case, the pregnancy of a woman is taken under special control. As a rule, prescribe treatment. In especially difficult situations, the question of abortion is raised.
Such a solution can be proposed for cerebral hernia and brain tumors, since these pathologies are incompatible with life. No less severe consequences are threatened by a reduced fetal
head size . This indicates the pathology of the brain, for example, the absence of its vital structures: hemispheres or cerebellum. According to such indications,
pregnancy is terminated at any time. If a reduced BDP is found in the third trimester, this may indicate an intrauterine growth retardation syndrome. In this case, drugs are urgently prescribed to improve the utero-placental blood flow (for example, the drug "Actovegin" and others).