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. During pregnancy, if a mother is Rh - negative and the fetus is Rh - positive, there can be complications. With the knowledge of the rhesus factor, new treatments (such as Rh immunoglobulin injections) during pregnancy could prevent harm (like hemolytic disease of the newborn) to the developing child.

• Option 1 is incorrect because the discovery of the rhesus factor actually reduced the number of deaths from transfusion reactions (not increased them) as transfusions could be better matched.
• Option 3 is incorrect because the discovery of the rhesus factor allowed for more appropriate use of donated blood (by matching Rh types), not less.
• Option 4 is incorrect because the number of blood types was not reduced by half; instead, the blood - typing system was expanded to include the Rh factor (e.g., O +, O -, A +, A - etc.).

Answer:

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