Down’s syndrome screening is mainly to check whether the fetus has congenital genetic problems. Maternal serum should be drawn at 12-16 weeks of pregnancy, through which the maternal serum is used to comprehensively analyze and assess the development of the fetus based on the maternal weight, gestational week and maternal height. Fasting is required before the maternal serum is drawn. If you drink or eat before this time, it can affect the monitored values and lead to inaccurate test results. Do not eat or drink after 12:00 pm on the first day, and have your blood drawn at 8:00 am on the second day, so that the results obtained from the test are more accurate. If you have a low risk of Down’s syndrome screening, this type of fetus is normal and you can let your baby be born. If there is an intermediate or high risk, further tests are needed to do amniocentesis or non-invasive DNA.