Family Nurse Practitioner Exam

A positive Coombs test in an Rh-negative pregnant woman indicates what?

1. The mother has autoantibodies against Rh-positive red blood cells

2. The fetus has autoantibodies against maternal RBCs

3. The mother does not have Rh factor against fetal RBCs

4. The fetus does not have RBC autoantibodies

The correct answer is: The mother has autoantibodies against Rh-positive red blood cells

A positive Coombs test in an Rh-negative pregnant woman is indicative of the presence of autoantibodies against Rh-positive red blood cells. This often occurs in cases where there has been mixing of maternal and fetal blood, typically during pregnancy or childbirth, leading to the mother's immune system producing antibodies against the Rh factor found on the red blood cells of an Rh-positive fetus. The presence of these autoantibodies can be significant in managing pregnancy because they can lead to hemolytic disease of the newborn if the fetus is indeed Rh-positive. The identification of these antibodies is crucial for monitoring and potentially intervening to protect the health of the fetus. In contrast, the other options do not accurately describe the implications of a positive Coombs test in this context. The fetus is not producing autoantibodies against maternal red blood cells, nor is the mother without Rh factor against fetal RBCs, which would suggest a lack of immune response. Understanding this relationship is vital for anticipating and mitigating risks associated with Rh incompatibility in pregnancy.