There are many causes of fetal arrest, and blood type O does not directly affect fetal arrest; if fetal arrest occurs due to blood type O, it may be related to the occurrence of hemolysis. If the mother of the fetus is blood type O, and the father is blood type A, B or AB, then the fetus is blood type A or B. The mother and the fetus will have a different blood type. Then there is a blood type incompatibility between the mother and the fetus, and the antibodies in the mother’s blood enter the fetal circulation and destroy the fetal red blood cells, thus affecting fetal growth and development and leading to fetal arrest. Therefore, in the presence of relevant risk factors, it is necessary to go to the hospital for prenatal blood serologic testing as early as possible in the preparatory period. If the antibody activity is low, the pregnancy can be prepared without any worry. If the antibody activity is high, medication can be used to reduce the antibody activity, thus ensuring the normal development of the fetus. During pregnancy, the blood should be tested regularly for antibodies and the fetus should be closely watched for the possibility of hemolytic disease. When the newborn is born, bilirubin should be monitored early and phototherapy should be carried out in time when the standard of phototherapy is reached. In addition, there are many causes of fetal arrest, which may also be due to abnormal embryo quality, chromosomal abnormalities, etc. It is recommended that couples undergo chromosomal testing, prepare for pregnancy scientifically, and maintain a healthy lifestyle.