There are possible combinations of blood types with the rH factors:
Rh factors are genetically determined. A baby may have the blood type and Rh factor of either parent, or a combination of both parents. Rh factors follow a common pattern of genetic inheritance. The Rh-positive gene is dominant (stronger) and even when paired with an Rh-negative gene, the positive gene takes over.
If a person has the genes + +, the Rh factor in the blood will be positive.
If a person has the genes + -, the Rh factor will also be positive.
If a person has the genes - -, the Rh factor will be negative.
I am aware that an infant receives one gene from the father and one from the mother, but what happens when the mother's Rh factor is negative and the newborn's is positive? What happens if the mother is O and the infant is A or B?
What happens within the placenta and to the maternal blood poles which are connected by open ended arterioles into intervillous spaces? Will the chorionic villi be "demolished" and exchange of materials isn't as possible?