Down’s syndrome screening at 16 weeks of pregnancy does not require water or food fasting. Down’s syndrome screening at 16 weeks of pregnancy refers to mid-trimester serum screening, which involves drawing blood from the mother’s peripheral vein, testing the mother’s serum for alpha-fetoprotein, human chorionic gonadotropin, and free estriol, and then calculating the risk of 21-trimester, 18-trimester, and neural tube defects in conjunction with the mother’s age, week of gestation, and body weight, among other factors. The serum indexes to be tested by Down’s syndrome screening are not directly related to whether or not the tested pregnant woman consumes water or food, and will not affect the test results just because she drank water before the test. Pregnant women generally do not need to prohibit drinking water before the Down’s syndrome screening test, and a normal diet will suffice. Down’s syndrome screening is only a method of prenatal screening, not a method of prenatal diagnosis, and cannot replace prenatal diagnosis, and cannot be used to make a decision to terminate a pregnancy based on the results of the screening. If the Down’s syndrome test is normal, you should follow the routine pregnancy tests in the pregnancy test booklet. If the screening results are abnormal, you need to go to the hospital in time, under the guidance of the doctor to do prenatal diagnosis, such as amniocentesis and other comprehensive examination, to avoid adverse consequences.