What is the difference between Positive + and Negative - blood?

Rh factor or Rhesus factor is a type of antigen present in the red blood cells of around 85% of total population. A person with Rhesus factor is called Rh positive (Rh+) and others are Rh negative (Rh-). Rh- blood does not have rhesus antibodies in their blood plasma.

If a mother is Rh – and father is Rh+ there are chances of the baby to be Rh+. If the mother and the foetus growing inside have different rhesus type, the child may suffer some kind of health problems. For the first child the problems are not so severe but the second child of these parents will face hemolytic or Rh disease in which the blood count of the newborn becomes dangerously low.