The dose of anti D gamma globulin given after term delivery for an Rh-negative mother and Rh-positive baby is –
**Core Concept**
The administration of anti-D gamma globulin to Rh-negative mothers after delivery is a crucial step in preventing the formation of anti-Rh antibodies and subsequent hemolytic disease of the newborn (HDN). This procedure involves the intramuscular injection of anti-D antibodies to neutralize any fetal Rh-positive red blood cells that may have entered the maternal circulation during delivery.
**Why the Correct Answer is Right**
The recommended dose of anti-D gamma globulin for Rh-negative mothers is 300 micrograms, administered within 72 hours of delivery. This dose is sufficient to neutralize the Rh-positive red blood cells that may have been transferred from the fetus to the mother during delivery. The anti-D antibodies bind to the Rh-positive antigens on the surface of the red blood cells, preventing the formation of anti-Rh antibodies and the subsequent risk of hemolytic disease of the newborn.
**Why Each Wrong Option is Incorrect**
**Option A:** This option is not a standard dose of anti-D gamma globulin for Rh-negative mothers.
**Option B:** This option is not a standard dose of anti-D gamma globulin for Rh-negative mothers.
**Option D:** This option is not a standard dose of anti-D gamma globulin for Rh-negative mothers.
**Clinical Pearl / High-Yield Fact**
It is essential to administer the anti-D gamma globulin within 72 hours of delivery to ensure its effectiveness in preventing the formation of anti-Rh antibodies. Failure to administer the anti-D gamma globulin within this timeframe may result in the formation of anti-Rh antibodies, leading to hemolytic disease of the newborn.
**Correct Answer: C. 300 micrograms.**