This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Medical, surgical and gynaecological illness complicating pregnancy, Subject name: Gynaecology & Obstetrics
Anti-D immune globulin is administered to Rh-negative women antenatally at 
Select and explain. 
A. 20weeks, B. 24weeks, C. 28weeks, D. 30weeks
C: 28weeks
Answer: C: 28weeks 
Explanation: The antepaum administration of anti-D immune globulin at 28weeks to Rh-negative women decreases the incidence of third-trimester alloimmunization from 18 to 20/1000 to 2/1000 patients.Reference: Practical guide to High-risk pregnancy and delivery; Chapter 14; Rh Alloimmunization