Down syndrome screening for high risk of trisomy 21

Down syndrome screening refers to the extraction of peripheral blood from pregnant women during the 16th to 18th week of pregnancy to conduct a blood cell biochemical test for chromosomal abnormalities in the fetus. If the test result of trisomy 21 in Down screening is high risk, it means that the fetus has trisomy 21, which is the risk of Down syndrome. This risk generally accounts for 1%, that is, only one out of 100 positive fetuses has a clear chromosomal abnormality, so pregnant women do not need to worry too much.

However, pregnant women at high risk of trisomy 21 should undergo further prenatal examinations, mainly amniocentesis and chromosome karyotype analysis, which is the gold standard for diagnosing fetal chromosomal abnormalities. However, for pregnant women with contraindications to amniocentesis, they can use the maternal peripheral blood fetal DNA test, which is a minimally invasive DNA test. The success rate of this test for trisomy 21 syndrome is very high.

The Down syndrome screening result shows a high risk of trisomy 21 syndrome, which indicates that the risk of the fetus suffering from trisomy 21 syndrome is relatively high. The main reasons for such screening results are:

1. The fetus does have trisomy 21 syndrome, so the screening result will be high-risk.

2. It may be caused by external factors, such as the pregnant woman is too old, has poor ovaries, or has problems with the quality of the eggs released; the pregnant woman smokes, drinks, stays up late, and other bad factors within three days before the Down syndrome screening; the pregnant woman is in the fever period, or suffers from other diseases during the Down syndrome screening; the specific age, pregnancy week, weight and other indicators provided by the pregnant woman during the Down syndrome screening are inaccurate; the technical strength and medical equipment standards of the hospital required for the Down syndrome screening are limited, which affects the accuracy of the test results.