Down syndrome screening for chromosomal abnormalities

If Down syndrome screening detects chromosomal abnormalities, it is very likely that there is a problem with the fetus's chromosomes. If the fetus is born at this time, it is very likely to be a deformed baby. Of course, the detection of chromosomal abnormalities still needs to be further confirmed through amniocentesis. Generally speaking, chromosomal abnormalities are probably caused by dietary problems, chemical pollution, drug abuse, etc., which can be avoided as much as possible. If a man has a problem, he can go to the hospital for a comprehensive examination.

Down syndrome screening is the abbreviation for prenatal screening test for Down syndrome. The purpose is to test the blood of pregnant women to detect the concentrations of alpha-fetoprotein, human chorionic gonadotropin and free estriol in the maternal serum, and to determine the risk factor of the fetus suffering from congenital idiocy and neural tube defects based on the age, weight, gestational age of the pregnant woman.

Normally, humans have 46 chromosomes in 23 pairs.

Trisomy 21, 18, 13 means that the fetus's 21st, 18th, and 13th pairs of chromosomes have one more than the normal 2, which is called XX trisomy. Trisomy 21 is Down syndrome. The incidence of chromosomal abnormalities increases significantly with the age of pregnant women. For example, the incidence of chromosomal abnormalities in pregnant women under 35 years old is 1:1185, while at the age of 35 it is as high as 1:335. Therefore, older pregnant women over 35 years old need to undergo chromosomal examinations.

Amniocentesis.

Amniotic fluid is extracted, the cells shed by the fetus in the amniotic fluid are cultured, and the chromosomes of the cells are tested (the fetus's 21 chromosomes are tested). Extracting amniotic fluid: 20 ml of amniotic fluid is collected. The risks are possible infection, amniotic fluid leakage, miscarriage, and the possibility of miscarriage (probability 1/1000). Cultivating the cells shed by the fetus in the amniotic fluid has a success rate of 98/100. Test the chromosomes of cells (test the 21 chromosomes of the fetus), with an accuracy rate of 100/100.