When should Rh immune globulin be given to an Rh-negative mother after delivery of an Rh-positive infant?

• A. Within 24 hours postpartum
• B. Within 48 hours postpartum
• C. Within 72 hours postpartum
• D. Only during pregnancy

Answer: (C)

Preventing Rh sensitization by neutralizing fetal Rh-positive cells that may enter the mother's circulation during delivery is the goal. For an Rh-negative mother with an Rh-positive infant, Rh immune globulin should be given within 72 hours after birth. Giving it within this window neutralizes fetal red blood cells before the mother's immune system can recognize them and form anti-D antibodies, which protects against Rh isoimmunization in future pregnancies. The dose can be adjusted if a larger fetomaternal hemorrhage is suspected, but the standard postpartum timing is within 72 hours.