HCG and MOM values, which are part of Down’s syndrome screening, are used to find out if the fetus has trisomy 21, trisomy 18, and the probability of neural tube abnormalities. The test results are divided into two parts: one is the risk value. If the risk is low, it means that the fetus has a low probability of having these chromosomal disorders. If it is a critical risk or high risk, further tests are needed. The other part is the MOM value, which is formed by the MOM value and mainly includes the measurement of HCG and AFP. If the HCG and MOM values are high, it means that the fetus still has a probability of developing trisomy 21. For abnormal results of this test, a visit to the genetics department is required for further prenatal diagnosis.