The best time for Down's screening is 15 ~ 20 weeks, which is the result of comprehensive judgment based on blood test, estriol, chorionic gonadotropin, alpha-fetoprotein and age, height, weight and last menstruation. The diagnosis rate is only 60-70%, and there is generally no problem with low risk. Risks exceeding the critical value require further examination, such as non-invasive dna testing or amniocentesis.
Extended data:
Precautions:
1, examination time of Down's screening. The best time for screening is 9~ 14 weeks of pregnancy, which is called early pregnancy screening. If you miss this time period, you need to enter the second trimester screening. Although you can also calculate the risk, if the final diagnosis is positive, it will do great harm to the mother.
2. When doing Down's screening, check the water on an empty stomach after 12 the night before, and come to the hospital on an empty stomach the next morning.
3. During prenatal screening, pregnant women need to provide more detailed personal data, including date of birth, last menstruation, weight, whether insulin-dependent diabetes, twins, smoking, abnormal pregnancy history, etc. Because the statistics of screening risk rate need to be revised according to the above factors, it is also very important to fill in the test sheet before blood drawing.
Baidu encyclopedia-down's screening
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