C because think about it 50 black and then 50 white
It’s because it has to be pg
The risk of maternal antibodies crossing the placenta and destroying the fetal red blood cells increases with each pregnancy. So, the outcome of the first RH+ baby is different from the second one.
<u>EXPLANATION: </u>
RH+ is a specific antigen present on the RBCs. A person that inherits these antigens has blood group RH+ and the ones who lack them have RH- blood group. Issues occur when the woman is RH- and the fetus is RH+ is the antibodies that cross the placenta and affect the baby's RBCs negatively.
This incompatibility occurs when father is RH+ and mother is RH-. The first-time pregnancy doesn't create much of the incompatibility. But if the fetus is RH+ the second time, results in life-threatening problems. During first time pregnancy, the RH+ antibodies are not present in the mother's blood.
But during the birth when placenta ruptures, the bloodstream enters into the mother's body and it starts stimulating the antigens of RH+ blood. Now, during the second pregnancy when the antibodies transfer from the mother to the placenta, RH+ antigens react with the fetal blood cells and destroys them.