Rh incompatibility is an issues in couples where Wife is Rh Negative
and Husband is Rh Positive.
If the child happens to be Rh Positive, its then there can be problem.
Usually the first pregnancy
is uneventful. During delivery, the childs blood cells can enter mothers blood stream and mother can develop Anti Rh Antibodies
Now in second pregnancy if the child is again Rh Positive, the ant Rhantibodies in mother blood can get into childs blood stream through placenta and can destroy the RBCs of the child.
This leads to fetal anemia
and problems of miscarriage
To prevent sensitization of mother in first pregnancy, mother should take Anti D injections (300 mcgs) at 28th and 32nd week and soon after delivery (If child is Positive)
Hope this answers your query
Thanks and Regards