How many hours should I fast for Down syndrome screening?

Many people usually pay more attention to some changes in their bodies. The Down syndrome screening test is a prenatal test mainly for those who are very worried about getting pregnant with Down syndrome. Usually, this test is started in the middle of pregnancy. However, you need to pay attention during the test. There are many precautions when doing it, you need to understand them clearly, otherwise the effect will not be good, or the correct result will not be obtained.

Down syndrome screening precautions

Every pregnant woman may have a baby with Down syndrome, so prenatal screening for Down syndrome should be performed. Down syndrome screening is performed between 15 and 20 weeks of pregnancy, using a combination of serological and B-ultrasound examinations, combined with a comprehensive risk assessment based on the pregnant woman’s age, weight, gestational age, medical history, etc.

1. Screening time: The best time is between 15 and 20 weeks of pregnancy.

2. Economical, simple, and harmless to the fetus. Although the results of Down syndrome screening cannot accurately determine whether the fetus is mentally retarded, it is the most economical, simple and non-destructive method to determine whether the fetus is mentally retarded. If the results are high-risk, amniocentesis can be further performed.

3. Screening method: A combined serological method is often used to screen for Down syndrome. Draw peripheral blood from pregnant women, extract serum (without fasting), test the concentration of alpha-fetoprotein (AFP) and serum chorionic gonadotropin (HCG) in the mother's serum, and calculate the risk factor based on the expected date of delivery, age, gestational age and weight of the pregnant woman at the time of blood drawing. This can detect 80% of congenitally retarded children.

4. Cost: About 100 yuan, but the standards vary from place to place and from hospital to hospital.

5. Preparation before the examination: There is no need to fast for Down syndrome screening, but it is related to the menstrual cycle, weight, height, accurate gestational age, and fetal age. Before the screening, pregnant women need to provide more detailed personal information, including date of birth, last menstrual period, weight, whether they have insulin-dependent diabetes, twins, whether they smoke, history of abnormal pregnancy, etc. Since the risk rate statistics of screening need to be corrected according to the above factors, it is also very important to fill out the test form before blood is drawn.

6. Down syndrome screening is not currently applicable to those who undergo in vitro fertilization or have twin pregnancies.