Often biochemical screening for the second trimester coincides with the time of the ultrasound examination, but this is not necessary. Often, blood tests are taken from 10 to 20 weeks of pregnancy, because it is in this time interval that you can fairly accurately determine whether there are chromosomal pathologies.
It is important not to engage in self-interpretation of perinatal screening for the second trimester, but to entrust it to a specialist. Blood pregnancy is studied in three ways - AFP (alpha-fetoprotoyin), hCG (chorionic gonadotropin) and free estriol. The reliability of these tests is about 70%, and therefore it is not necessary to faint if any indicator differs from the norm. If desired, a woman may refuse to conduct biochemical screening for the second trimester of pregnancy.
Norms of ultrasound screening for the 2nd trimester
In this period, the diagnosis is carried out in order to confirm or disprove the possible pathology, as well as the presence of multiple pregnancies. The volume of amniotic fluid, the position in the uterus of the fetus and the placenta is estimated. Defects of the structure of the bones of the skull and extremities, the ventricles of the brain and the umbilical arteries are determined.
Decoding of ultrasound screening in the 2nd trimester is carried out by the precinct-gynecologist, but does not present much difficulty for self-study. So, all the bones of the limbs must be the same length, the skull, and especially its facial part without visible deformations in the form of non-affection of the nasolabial triangle.
Ultrasound screening for the 2nd trimester often answers the question that most parents are interested in - a boy or a girl? In 90% of cases this is confirmed later. A great advantage of the second ultrasound is that now you do not need to endure a complete bladder and in any preparation for the study there is no need.