A low pappa value in early Down’s syndrome screening does not directly confirm the diagnosis of Down’s syndrome, and pregnant women should undergo further testing. pappa is the English abbreviation for pregnancy-associated protein A. Under normal circumstances, the level of pregnancy-associated protein A in early pregnancy will rise with gestational weeks, the lower the level of the value suggests that the fetus for the higher risk of Down’s syndrome, but this is only a prenatal screening means, with a certain degree of error, and can not be directly used as a diagnostic method of obstetric diagnosis of Down’s syndrome fetus. Pregnant women with low levels of pregnancy-associated protein A should undergo further tests to confirm the diagnosis, such as prenatal non-invasive DNA testing, prenatal screening ultrasound, etc., and if necessary, chorionic villus sampling and amniocentesis should be performed to confirm the diagnosis. When the results of the labor test are abnormal, pregnant women should undergo further examination under the guidance of a professional physician, and terminate the pregnancy in time if necessary, so as not to lead to an adverse outcome of the pregnancy.