KTR stands for coccyx-parietal size, and it is important in the first trimester of pregnancy to accurately determine the duration of pregnancy and, on the basis of this, the timeliness of fetal development. The error in setting the deadline for KTR is only 1 day, in rare cases - 3 days.
How is the CTE of the fetus measured?
KTP measurement is performed during a planned ultrasound. In this case, the uterus is scanned in different planes, after which the largest indicator of the length of the fetus is selected. It is this indicator that is considered true in this period. However, it should be borne in mind that the embryo will grow by another millimeter the next day.
Why check the CTE of the fetus for weeks?
CTF of the embryo allows to track its development by weeks and to diagnose the deviations in time. About deviations speak, when average parameters KTR of a fetus considerably deviate from norm.
At 10-12 weeks the first planned ultrasound is performed, during which the development of the fetus is evaluated, the work of his heart, the sex of the baby is determined. This study specifies the duration of pregnancy by measuring the size of the child in millimeters.
Using the results table of the fetal CTF, one can judge by weeks the normal development of the baby in the first trimester of pregnancy, since the average values of the norm for the weeks of pregnancy are indicated in the table (in the table).
On the presented table of the KTP of the fetus one can see that the indices are available only up to 13 weeks. The fact is that it is at the time to 13 weeks that these data are most indicative. The last measurement of CTF of the fetus can be carried out at 15 weeks. After 16 weeks, the CTE of the fetus is not evaluated, because other characteristics come to the fore.
It is advisable to make a CTE measurement at the time of 11-12 weeks - the earlier this procedure is done, the faster the question will be resolved with the presence or absence of malformations of the fetus. And the first trimester is suitable for this most.
To decode KTR values it is necessary with the doctor, since it is rather difficult to try to understand all the wisdoms of this measurement independently. One can clearly see - up to 12 weeks, the CTE of the fetus increases by 1 mm per day, and starting from week 13 - by 2-2.5 mm. This means that the child begins to grow actively, as all of his systems and organs are fully formed.
Decoding of KTR indicators by weeks
At a period of 6 weeks, the KTR of the fetus is between 7 and 9 mm. As early as week 7, the CTR of the fetus increases to 10-15 mm. At 10 weeks, the CTE of the fetus is 31-39 mm. And at 12-13 weeks, this indicator increases to 60-80 mm.
The CT of the fetus at 14 weeks is about 86-90 mm. And already in 16-17 weeks, the CTE of the fetus is no longer measurable. This indicator is replaced by other, more important characteristics at this stage.
Why exactly from the crown to the tailbone?
The entire first trimester of the baby is measured from the crown to the tailbone. In another way, it is difficult to measure it because of its position inside the uterus. He is very "crooked", if I may say so. Yes, and the size of the legs are still very small. A little later, he will straighten up a little and his measurement will be possible from the top to the heels.
But even after the pod legs grow to their full length, it will be difficult to measure the child in full growth, because the legs remain bent. The full length of the fetus can be obtained only by adding the values of separately measured measurements from the crown to the coccyx, thigh and shin.
But usually doctors do not do this, defining everything individually and on this basis basing their conclusions on the development of the baby. Folding results is the fate of mothers who want to boast of the full growth of their child.