The hemolysis test refers to the ABO hemolysis test, if the blood type of the pregnant woman is O and the husband’s blood type is A, B or ABO, the baby conceived may have ABO hemolytic disease, so it is recommended to start the hemolysis test within the first trimester of pregnancy. The second hemolysis test should be done at 28-30 weeks of pregnancy. After that, the test should be repeated every month according to the pregnant woman’s condition and the development of the fetus, because the individual immune response of the fetus is different, and it can be combined with ultrasound to observe the condition of the fetus in the womb. The significance of hemolysis screening for pregnant women is the early prevention and diagnosis of neonatal hemolysis. In case of mismatch between the blood type of the pregnant woman and the fetus, the red blood cells of the fetus are covered by the immunoglobulin G (IgG) antibodies of the mother and neonatal hemolysis can occur, which can lead to a series of adverse phenomena such as miscarriage, premature birth and neonatal bilirubin encephalopathy, so it is necessary to have a hemolysis test during pregnancy.