How would you treat a mother with type A Rh-negative blood who is pregnant with a type O Rh-positive baby?
A) A dose of RhoGAM at 28 weeks and following delivery
B) A high dose of RhoGAM and then a low dose of RhoGAM
C) A dose of RhoGAM only if there is a trauma or premature termination of pregnancy
D) RhoGAM is not necessary in this situation because there is no compatibility issue

Question

Quizplus · Accepted Answer

RhoGAM is necessary in this situation because the mother is Rh-negative and the baby is Rh-positive, and if fetal blood enters the mother's body, then the mother will produce antibodies to the Rh antigen (D antigen). An Rh-negative mother should be treated with RhoGAM at 28 weeks to prevent production of Anti-Rh (anti-D) antibodies in the event that there is any exchange of blood between the mother and fetus. A second dose is given within 72 hours of delivery to allow the RhoGAM to coat any fetal red blood cells (RBCs) that may have crossed to the mother's blood stream during delivery. Coating the fetal RBCs prevents the mother's immune system from recognizing the cells as foreign, thus preventing antibody production to the Rh-antigen if the baby is Rh-positive. By preventing antibody production, future fetuses are not at risk for hemolytic anemia and erythroblastosis fetalis due to Rh incompatibility. Early in pregnancy, when the fetus is small, the dose is lower because the amount needed to neutralize the small amount of blood in the fetus is low. Later, when the fetus is larger, there is the possibility that more blood could be exchanged between mother and fetus, so the dose of RhoGAM required to neutralize the fetal cells in the mother is larger.

How Would You Treat a Mother with Type a Rh-Negative