Final answer:
Rh antibodies are IgG antibodies that cause extravascular hemolysis. This occurrence is significant in Rh-negative individuals exposed to Rh-positive blood, such as during transfusion or pregnancy with an Rh-positive fetus, leading to hemolytic disease of the newborn.
Step-by-step explanation:
When considering Rh antibodies and their association with hemolysis, the correct statement is that they are IgG antibodies and cause extravascular hemolysis. The process is triggered in cases where an Rh-negative individual is exposed to Rh-positive red blood cells, which can lead to the production of anti-Rh antibodies. The first exposure to Rh-positive blood often does not cause a strong immunological reaction, but upon subsequent exposures, anti-Rh IgG antibodies can activate the immune system that results in the destruction of Rh-positive red blood cells. This destruction primarily occurs outside of blood vessels in the spleen and liver, not within the blood vessels themselves, hence the term extravascular hemolysis.
In the context of pregnancy, when an Rh-negative mother is carrying an Rh-positive fetus, she can develop these antibodies, which can cross the placenta and attack the fetal red blood cells, potentially leading to hemolytic disease of the newborn. This condition is preventable by treating the mother with RhoGAM to prevent the immune response against the baby's red blood cells. Therefore, the statement that Rh antibodies are IgG and cause extravascular hemolysis is correct.