Pregnant women with blood type O should be aware of hemolysis in the newborn and should be monitored regularly for blood group antibodies during pregnancy. Pregnant women with blood type O may experience hemolysis in the newborn due to blood group incompatibility between mother and child. If the mother has blood type O and the fetus has blood type A or B, the A antigen or B antigen in the fetus’s blood cells will enter the mother’s body and stimulate the mother’s cells to produce antibodies, and the antibodies produced by the mother will pass through the placenta and enter the fetus, thus leading to the occurrence of hemolysis. Therefore, if a pregnant woman’s blood type is O, she needs to monitor the concentration of blood group antibodies during pregnancy. If the concentration of blood group antibodies rises progressively, there is a high likelihood of hemolysis, and pharmacological interventions (e.g., immunoglobulin, etc.) are needed. Pregnant women with blood group O should pay attention to hemolysis in the newborn and regularly monitor the blood group antibody level, and if there is any abnormality, it should be treated in time to avoid adverse consequences.