In the postpartum setting, RhIg is typically given after delivery of which type of newborn?

• A. An AB0-incompatible newborn
• B. An Rh-negative newborn
• C. A newborn with jaundice
• D. An Rh-positive newborn

Answer: (D)

The idea is to prevent maternal sensitization to the RhD antigen. Rh immune globulin is given postpartum to an Rh-negative mother when the newborn is Rh-positive, because fetal Rh-positive red cells can enter the mother’s circulation during delivery. If the mother is Rh-negative and exposed to RhD positive cells, she can form anti-D antibodies that would threaten future pregnancies. The passive anti-D in RhIg binds those fetal cells and hides the D antigen from the mother’s immune system, preventing the formation of anti-D antibodies.

If the newborn were Rh-negative, there would be no RhD antigen exposure to the mother, so RhIg is not needed. The other scenarios listed (such as AB0 incompatibility or jaundice) do not by themselves determine the need for RhIg.