The first screening or screening for the first trimester involves a comprehensive examination, which is carried out by taking blood from the vein and performing an ultrasound for 11-14 weeks. It allows to determine the risk of pathological changes in the fetus, and, first of all, it is aimed at revealing the malformations of the neural tube, Down's syndrome and Edwards syndrome, gross violations in the development of other organs and systems.
With the help of ultrasound determine the physique of the future child, whether everything is "in place", whether the handles and legs are properly located. In addition, special measurements are made (measure the thickness of the cervical fold). The doctor examines the blood flow in the fetus, the work of the heart, the correspondence of body length to the timing of pregnancy. Also determine the thickness of the collar space in the embryo. If its value differs from the norm, then the risk of genetic disorders increases.
The blood test establishes the content of RAPP-A (plasma protein) and hCG (human chorionic gonadotropin) - the so-called "double test".
HCG is one of the major hormones during pregnancy. If its amount is lowered, then this is evidence of the pathology of the placenta. Elevated levels of the hormone are very often due to chromosomal abnormalities in the fetus or multiple pregnancies. The test for RAPP-A determines the produced protein A in the blood. With Down's syndrome or Edwards syndrome, as well as other congenital malformations of the fetus, its level is significantly reduced.
If the results of a comprehensive survey reveals a high risk of pathology in the fetus, then conduct additional diagnosis. Pregnant amniocentesis is the study of amniotic fluid. It allows you to diagnose chromosomal and some genetic diseases. A chorion biopsy (biopsy of villus chorion) involves the production of cells that form the placenta, to study congenital and hereditary diseases of the fetus.
First trimester screening is not required for all pregnant women. It is sent to those expectant mothers who have a higher risk of pathology. The risk group includes women after 35 years; those who have sick people with genetic pathologies in the family; women who previously had miscarriages or were born children with genetic abnormalities, or young mothers, in the early stages of pregnancy, survived viral diseases.