What happens to fetus if mothers is not vaccinated with RH gram?

If the mother is Rh negative and the fetus is Rh positive, their blood can mix during pregnancy or delivery. This can cause the mother's immune system to produce antibodies against the Rh factor, which can cross the placenta and attack the fetus's red blood cells. This condition is called Rh disease (Rh factor incompatibility) or erythroblastosis fetalis.

Rh disease can lead to anaemia in the fetus and newborn 赤ちゃん. It can also lead to jaundice, a condition in which the skin and whites of the eyes turn yellow due to a build-up of bilirubin, a waste product from the breakdown of red blood cells. In severe cases, Rh disease can lead to heart failure, brain damage, or even death.

To prevent Rh disease, Rh negative mothers are usually given an injection of Rh immune globulin (RhIg) at around 28 weeks of pregnancy and following delivery of an Rh positive newborn. RhIg binds to any Rh-positive red blood cells that may have entered the mother's circulation and prevents her immune system from producing antibodies against them.