Dose of anti D immunoglobin is –
**Core Concept**
Anti-D immunoglobulin is a medication used to prevent RhD alloimmunization in RhD-negative pregnant women or those who have undergone a miscarriage or abortion. It works by neutralizing any fetal RhD-positive red blood cells that may enter the maternal circulation, thereby preventing the formation of antibodies against RhD.
**Why the Correct Answer is Right**
The standard dose of anti-D immunoglobulin is 300 micrograms, administered intramuscularly at 28 weeks of gestation and again within 72 hours after delivery, miscarriage, or abortion. This dose is sufficient to neutralize the RhD antigen on fetal red blood cells and prevent the activation of the complement system, which would lead to the production of anti-RhD antibodies.
**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because the dose of anti-D immunoglobulin for routine administration is 300 micrograms, not 100 micrograms.
**Option B:** This option is incorrect because the dose of anti-D immunoglobulin for post-delivery administration is 300 micrograms, not 500 micrograms.
**Option C:** This option is incorrect because the dose of anti-D immunoglobulin for post-miscarriage or abortion administration is 300 micrograms, not 200 micrograms.
**Clinical Pearl / High-Yield Fact**
It is essential to note that anti-D immunoglobulin should be administered within 72 hours after delivery, miscarriage, or abortion to be effective in preventing RhD alloimmunization.
**Correct Answer: D. 300 micrograms**