When a woman with blood type O and a man with blood type AB have a baby, there is a possibility of hemolysis. For a woman with type O blood and a man with type AB blood, the child born from the combination of these two blood types may have type A or type B blood, and if the mother’s body has been exposed to type A or type B antigens, and there are antibodies against A or B in her body, hemolysis may occur in the child. However, if the mother has not been exposed to A or B antigens, and there are no anti-A or anti-B antibodies in her body, then the child will not get hemolytic disease. Pregnant women should not be anxious about whether or not their child may develop hemolytic disease, but rather, they should take regular obstetric tests during pregnancy and seek medical attention if the child is born with any abnormalities.