Early Down’s syndrome prenatal screening is generally referred to as early Down’s syndrome prenatal screening test, and it is best to complete the early Down’s syndrome prenatal screening test at 11 weeks to 13 weeks + 6 days of pregnancy in accordance with the requirements of the maternity test. Prenatal screening for Down’s syndrome is done by taking the blood of the pregnant woman to test the concentration of free estriol, beta-chorionic gonadotropin, and alpha-fetoprotein, and then combining with the time of pregnancy, age, and weight of the pregnant woman to determine the risk of neural tube developmental defects and Down’s syndrome in the fetus. Early prenatal screening for Down syndrome is usually performed between 11 weeks and 13 weeks + 6 days of pregnancy. Timely prenatal screening for Down syndrome can help to analyze the presence of Down syndrome in the fetus. For pregnant women with abnormal Down syndrome prenatal screening results, amniocentesis may also be needed to help clarify the diagnosis.