The first comprehensive examination of the baby is carried out long before his birth. So, for a period of 11 to 14 weeks, obstetrician-gynecologists recommend that almost all of their patients conduct a first trimester screening. Do not be afraid of this phrase, with a future mother and child they will not do anything terrible. This study includes routine ultrasound diagnostics and a special blood test from a vein, which is taken from mom in the laboratory. That is why screening for the first trimester is also called a double test.
The indicated period is the most favorable for identifying possible genetic failures in the baby. Based on the results of the analysis and ultrasound, a specialist can identify various malformations of organs or systems of the body and predict whether the child is likely to have Down, Klinefelter or Edwards syndrome. First trimester screening shows only the likelihood of genetic diseases, and in the course of further studies they can either be confirmed or disproved.
The principle of this study is based on the fact that during an ultrasound the doctor not only looks to see if the baby’s legs and arms are in place, but also takes certain measurements. The length of the baby is measured, its compliance with the age of the fetus is checked. A sufficiently important indicator is the thickness of the cervical fold - the collar zone. This is the area between the soft tissues and the skin in which fluid accumulates. An excessive increase in its size indicates a high risk of the development of genetic diseases. The nasal bone is also measured: by the end of the 3rd month of pregnancy, it should already be about 3 mm.
They will tell you if the specialist does not like the results of the first trimester screening. The thickness norms for the collar zone, for example, vary depending on the gestational age: at 11 weeks, its average thickness is 1.2 mm, and at 14 - 1.5 mm. But there is no reason to panic if this zone is 2-2.5 mm. Even if the values are increased, do not panic. Given that the accuracy of the measurements depends on the equipment and the level of professionalism of the doctor of ultrasound diagnostics, it makes no sense to evaluate the results of this study without analysis.
In the laboratory, first-trimester screening is a biochemical analysis during which the content of free b-hCG and plasma protein A (PAPP-A) in the blood of the expectant mother is examined and compared with the average values that should be. The laboratory on the form indicates the results obtained and their norms for each week. Only a combination of tests and ultrasound results can give a relatively clear picture of how the pregnancy proceeds. Screening for the first trimester cannot be considered reliable if you only donate blood or just
do an ultrasound scan. Moreover, these studies should be done almost on the same day to rule out the possibility of error due to time differences.
Do not abandon the study just because you are afraid to get bad results. Even if this happens, no one can force you to terminate the pregnancy, you will simply be advised to go to further studies to accurately confirm or refute the diagnosis. But if you know in advance about possible problems, you will be able to adequately prepare for the birth of a special baby.