Question

how did the discovery of the rhesus factor affect society?
more patients died from having a transfusion with the wrong rhesus factor.
new treatments during pregnancy could prevent harm to the developing child.
less donated blood could be used in the treatment of patients.
the number of blood types was reduced by half.

Explanation:

The discovery of the rhesus factor led to new medical - knowledge. In pregnancy, it allowed for new treatments to prevent harm to the fetus in cases where the mother and fetus have different rhesus factor statuses. For example, Rh - immune globulin can be given to Rh - negative mothers to prevent their immune system from attacking the Rh - positive fetus.

Answer:

New treatments during pregnancy could prevent harm to the developing child.