Rh system is one of the blood grouping systems just as ABO system. It is derived genetically due to combination of parent’s DNA. It is basically of two types Rh+ and Rh- i.e. if a person has Rh antigen on RBC then he is said to be Rh+ if not then Rh-.
If the mother is Rh- and the fetus is Rh+, during the pregnancy period or during delivery the blood of the child might come in contact with the mother’s blood. This will lead to formation of antibodies against Rh antigen in mother’s blood. Later during second pregnancy if the child is again Rh+, Rh antibodies will enter the child’s blood and will destroy the child’s RBC’s. This condition is known as Erythroblastosis fetalis. This can cause various problems in child such as jaundice, spleen problems etc. To prevent such complications mother is given an anti-D injection at 28th week of pregnancy.
