Which of the following blood group antibodies is most likely to cause hemolytic disease of the newborn?

Hemolytic disease of the newborn (HDN) is primarily caused by incompatibility between the blood types of a mother and her baby, specifically when the mother produces antibodies against the baby's red blood cell antigens. The most significant and common antibody associated with HDN is Anti-D. This occurs when an Rh-negative mother carries an Rh-positive baby. If fetal red blood cells that express the D antigen enter the maternal circulation, the mother's immune system can produce antibodies against this antigen, leading to hemolysis of the fetal red blood cells.

This condition is particularly concerning during the first pregnancy as the mother may not have produced these antibodies yet, but it can become more severe with subsequent pregnancies involving Rh-positive fetuses. The presence of Anti-D is a crucial factor in the risk of developing HDN as it directly targets the fetal Rh-positive red blood cells.

In contrast, while the other antibodies, such as Anti-Jka, Anti-Fya, and Anti-K, can also cause hemolytic reactions, they are less commonly associated with HDN. Their clinical significance varies and tends to be less severe than that of Anti-D in the context of maternal-fetal blood type incompatibility. Thus, the emphasis on Anti-D as the primary concern in cases