Ultrasound research, which will have to be done by the pregnant woman on the entire gestation period, is the only source of more or less reliable information about the term of pregnancy, the growth and development of the fetus, the presence of its pathologies or defects, and so on. It is for this purpose that fetometry is carried out, that is, the establishment of a biparental head size, which is of interest to gynecologists and obstetricians of any women's consultation. This indicator is rightfully considered to be one of the most important, and is determined in any course of gestation. However, not every woman fully understands that this is the BDP of the fetus, why these data are needed, what norms exist and so on.
What is the biparietal size of the fetus?
These data are obtained by visualizing waves on the ultrasound screen, which are similar to the level of the third ventricle of the brain. BDP during pregnancy shows the actual and largest distance between the oppositely located walls of the bones of the crown of the skull of the baby. That is, it characterizes the size of the child's head and, as a consequence, shows the correspondence of the state and degree of development of the nervous system and the period of gestation.
Biparietal size or BPD is necessary to confirm safe for both the fetus and the mother, the passage through the birth canal and the selection of the most optimal type of delivery and tactics of medical personnel during the removal of the burden. If the ultrasound of the fetus BDP shows a significant mismatch between the size of the head and the birth canal of the mother, which may occur due to various reasons, a planned cesarean section is prescribed.
Norms of BDP for weeks
There are so-called weekly BDP guidelines, which are specially developed for each term of gestation, which greatly facilitates the diagnosis. Studies can be carried out on a first-come-first-hand basis, but the most reliable information about the compliance of the child's development with the gestation period is obtained in the second or third trimester of pregnancy.
To understand what is the biparietal size of the fetus and whether it corresponds to your results with the generally established norms, it is worthwhile to familiarize yourself with the table in which BDP data is presented for each week. These tables are already included in the program of the ultrasound machine and it is on their basis that a conclusion is issued. The operator or the doctor independently selects the required type of data and sets it directly before the study itself. Do not panic immediately if the final results are not ideal, there are always fluctuations within certain limits. The final diagnosis is whether the BDP norm corresponds to your gestation period. For example, a BPR of 18 mm is equivalent to both the 11th and 12th week of pregnancy.
Features of what BDP means on ultrasound
The combination of such an index as the occiputo-frontal size with BPR data allows to judge on what level of development the fetus is at and how long the pregnancy actually takes place. After all, it is from the period of gestation that a general evaluation of the degree of development of the child begins, whether he is full or not. BDP size for weeks provides the doctor with the necessary information to help establish the condition and size of the brain based on the volume of the cranium and, consequently, the entire nervous system of the baby.
The peculiarity of this indicator is that the data characterizing its growth slows down as the fetus grows up. So, for example, BDP at 12 weeks, and more specifically its growth, is about 4 millimeters per week. By the end of the gestation period, the BDP indicator at 33 weeks is already 1.2 or 1.3 mm maximum.
Thus, a correct understanding of what a biparietal fetal size and what it means is helping in time and fully assess the degree of growth and development of the fetus in the maternal womb.