<prompt> Anti-D immune globulin is administered to Rh-negative women antenatally at20weeks24weeks28weeks30weeks  <response>: The antepaum administration of anti-D immune globulin at 28weeks to Rh-negative women decreases the incidence of third-trimester alloimmunization from 18 to 201000 to 21000 patients.Reference: Practical guide to High-risk pregnancy and delivery; Chapter 14; Rh Alloimmunization 