The main purpose of Down’s syndrome screening for pregnant women is to check whether the baby in the womb has Down’s syndrome. The time to do Down’s syndrome screening is the 16th to 18th week of pregnancy, and it is generally recommended that pregnant women go for the best screening around the 16th week of pregnancy, when the fetus is not too big and can be dealt with in time if any problems are found. Women who are pregnant need to go to the hospital for Down’s syndrome screening around the 16th to 18th week of pregnancy. The test involves taking the mother’s blood from a vein and examining her blood to detect chromosomal abnormalities or neurological defects in the fetus. Usually, Down’s syndrome screening is only used as a primary screening for Down’s syndrome, with a detection rate of about 60%. If the risk of Down’s screening is low, the risk of fetal abnormalities is very low. However, since the accuracy of Down’s screening is limited, the probability of fetal abnormalities cannot be completely excluded. If the Down’s screening result shows a high risk, it does not necessarily mean that the fetus has a problem and further testing is needed. Amniocentesis or non-invasive dna screening is usually recommended to further determine the likelihood of the baby’s malformation and then to determine whether to proceed with the pregnancy. The best time for a pregnant woman to undergo Down’s syndrome screening is the 16th week of pregnancy. If the Down’s syndrome screening shows a high risk, the pregnant mother will need to undergo further testing.