There is a possibility of hemolytic disease of the newborn occurring in a woman with blood type B and a man with blood type O.
There are two possible blood types for a child born to a woman with blood type B and a man with blood type O, i.e., type B and type O. If the child’s blood type is O, it is different from the mother’s blood type and there is a possibility of neonatal hemolysis, but the chances are relatively low. If the child’s blood type is O, which is the same as the mother’s blood type, neonatal hemolysis usually does not occur.
Neonatal hemolysis can occur when the mother and fetus have different ABO blood groups or different Rh blood groups, with neonatal hemolysis caused by different ABO blood groups being more common. Hemolysis due to different ABO blood groups often occurs in the first trimester, while hemolysis due to different Rh blood groups often occurs in the second trimester.
It is recommended to consult an obstetrician and to perform regular checkups during pregnancy to determine the fetal blood group in order to assess the risk of hemolysis in the newborn and to take proactive measures to prevent it.