A mother is pregnant with her first child. The mother has Rh^— blood and the infant has Rh⁺ blood. What is likely to occur during pregnancy/birth?

• A. The mother is “sensitized” to the Rh antigen and eventually begins to create anti-Rh antibodies.
• B. The infant’s immune system immediately attacks the mother’s blood, resulting in a severe cytotoxic reaction.
• C. The infant’s Rh antigens will break down so that the infant’s blood type matches the mother’s blood type.
• D. If the mother is not given RhoGAM, her immune system will attack the infant’s RBCs, causing major damage.

Answer: (A)

Verified step by step guidance

1. Understand the Rh blood group system: Rh-positive (Rh+) means the presence of the Rh antigen (D antigen) on red blood cells, while Rh-negative (Rh-) means the absence of this antigen.
2. Recognize that if an Rh-negative mother is carrying an Rh-positive fetus, fetal red blood cells carrying the Rh antigen can enter the mother's bloodstream, especially during delivery.
3. Explain that the mother's immune system may recognize the Rh antigen as foreign and become sensitized, leading to the production of anti-Rh antibodies (IgG type) against the Rh antigen.
4. Note that these anti-Rh antibodies can cross the placenta in subsequent pregnancies and attack the red blood cells of an Rh-positive fetus, causing hemolytic disease of the newborn (erythroblastosis fetalis).
5. Highlight the preventive measure: administration of RhoGAM (anti-Rh immunoglobulin) to the Rh-negative mother during and after pregnancy to prevent sensitization and antibody formation.