Down screening only has a high risk of neural tube defects, and pregnant women can wait until 20-24 weeks of pregnancy for a 4-D ultrasound to screen for fetal neural tube malformations. Down’s syndrome screening checks for the risk of trisomy 21, neural tube defects. with a high risk of trisomy 21, there is an increased likelihood that the fetus will be a Down’s baby, and further amniocentesis will be required. If the risk of neural tube defects is high, the fetus may have spina bifida, anencephaly, etc. A 4D ultrasound is needed to perform a systematic ultrasound examination to screen for fetal malformations. A high risk of neural tube defects on Down’s screening indicates an increased likelihood of fetal abnormality, but it is not definitive. Pregnant women need to undergo further tests to confirm the diagnosis, and if the ultrasound examination reveals that the fetus does have structural abnormalities, they need to seek medical treatment promptly.