The high risk of Down syndrome is not very high, and there is also a false positive rate, which requires further screening as prescribed by your doctor. Down’s syndrome screening is a serological screening method to detect chromosomal disorders in the fetus, which needs to be performed by a professional physician at 15-20 weeks of gestation, and calculates the risk of developing the disease by detecting the triple screening of alpha-fetoprotein, human chorionic gonadotropin, and free estriol in the serum of a pregnant woman, and the cut-off value may vary in different regions. The results of Down’s syndrome screening are affected by various factors such as the age, gestational week and weight of the pregnant woman, and the accuracy of the test is only 60%-75%, with a false-positive rate of 5%. Therefore, when the results indicate a high risk, further prenatal diagnosis such as amniocentesis is required under the guidance of the doctor in order to rule out the risk of Down’s syndrome in the fetus.