The woman’s blood type O has no special effect on pregnancy, but she should be alert to ABO hemolysis in the newborn. There are various ways to categorize blood types, according to whether the surface of red blood cells contains A antigen or B antigen, they can be classified as A, B, AB, O. Blood type O does not contain either A or B antigen, but it is still a common blood type in clinical practice and does not have any other special effects on fertility. At present, there are sufficient blood products in reserve, and even if there is hemorrhage during delivery and O-type blood is needed, blood transfusion can be carried out in time to save the mother’s life. However, type O mothers need to be alert to neonatal ABO hemolysis, which occurs mainly when the mother has type O blood and the fetus has type A or B blood. Most newborns with ABO hemolysis do not have obvious symptoms, but a few may have jaundice.