It is best to take the test around the 16th-20th week of pregnancy. Down’s syndrome is a very necessary test during pregnancy, which can effectively detect chromosomal abnormalities or neural tube malformations in the fetus. However, the results of the Down’s test are not 100% accurate, and pregnant women should not be overly nervous if the results show abnormalities after receiving the test results, because after the Down’s test has abnormalities, amniocentesis will be performed to further determine the condition. The amount of amniotic fluid is most sufficient between 16-20 weeks of pregnancy, and amniocentesis at this time will not harm the fetus, so it is best for pregnant women to get hold of the Down’s syndrome screening within this period.