What are the normal values ​​and precautions for Trisomy 21?

For most older mothers, the chances of experiencing some abnormal conditions during pregnancy will be relatively higher. It is best to choose the right time to do Down syndrome screening during pregnancy to check for some diseases in the fetus. Once any abnormality is found, it can be treated in time. Below, the editor will introduce some common precautions about trisomy syndrome.

Under normal circumstances, humans have 46 chromosomes in 23 pairs. Trisomy 21, 18, and 13 means that the fetus's 21st, 18th, and 13th pairs of chromosomes have one more than the normal two, which is called XX trisomy. Trisomy 21 is Down syndrome.

Pregnant women of any age may have a fetus with chromosomal abnormalities, but the incidence of chromosomal abnormalities increases significantly with the age of the pregnant woman. For example, the incidence of chromosomal abnormalities in pregnant women under 25 years old is 1:1185, while at the age of 25 it is as high as 1:335. Therefore, pregnant women over 25 years old need to undergo chromosomal examinations.

1. Down syndrome screening is a possibility test: the high-risk group only means that the fetus is more likely to be a child with Down syndrome, and the low-risk group may also have Down syndrome.

2. About 1/10 of all pregnant women are high-risk groups, and 1-2/100 of the high-risk groups are Down syndrome babies, which means that 1-2/1000 pregnant women are Down syndrome babies.

3. When the blood test screening value is greater than 1/270, it means you are in a high-risk group, and the normal value is around 1/700. The international standard is 1/270

4. Down syndrome screening values ​​are corrected values. The factors that affect the Down syndrome screening value mainly include: pregnant woman’s age, gestational age, fetoprotein secreted by the fetus, human chorionic hormone secreted by the placenta, drug factors, genetic factors, etc. Taking Dolly Mam to protect the fetus may cause human chorionic gonadotropin to exceed normal values, which may affect the Down syndrome screening value.

Before preparing for Down syndrome screening, you should do some preparation in advance to minimize the adverse effects of medications, etc. on the test results tomorrow. If any abnormalities are found during the examination, further examinations should be conducted in a timely manner, and appropriate treatment measures should be taken under the guidance of a professional obstetrician.