A high PAPP-A value in the third trimester of pregnancy is usually normal, but other tests should be ordered if necessary. Down’s syndrome screening is a comprehensive test that is not very accurate in the early stages of pregnancy, so if it is done at this time it is likely to be high, and since PAPP-A is mainly a large glycoprotein produced by the placenta and meconium, the higher the days of pregnancy the higher the PAPP-A value will be, and it will continue to be high until delivery. In addition, although high PAPP-A values in the third trimester of pregnancy are generally normal, it is still recommended that patients do regular prenatal screening under the guidance of their doctors and try to pay more attention to fetal movement in general. PAPP-A is one of the data of Down screening and needs to be judged in combination with other data. If the risk is high, the patient is advised to undergo further tests such as non-invasive DNA or amniocentesis in this case.