blood group matching - b4 marriage

yes it should be considered but many people know little abt it..so ppl shud be made aware of it that blood group should match...but if u cant help but marrying that person den its fine coz abt cross matching for birth of a child dere r injections which a mother should take after birth of their first child and surely nothing will happen to her next child...deres sumthn called Rh factor which should match...for that to avoid u should take it into consideration but its not like sum1 will die or nythn...yet it should be considered dats y it is in premarital counselling