Ans. is b, i.e. Single dose of 1500 IU at 28 weeksPostpartum prophylaxis in Rh negative womenRh anti-D IgG is administered intramuscularly to the mother following child birth or abortion.Timing:It should be administered within 72 hrs or preferably earlier following delivery or abortion.Should be given only if the baby born is Rh +ve and Direct Coombs Test done on baby's blood is negativeIn case 72 hrs is over, it can be given upto 28 days after delivery to avoid sensitization.Dose:300 microgram following delivery.50 microgram following induced abortion, ectopic pregnancy or CVS in 1st trimester.In case of pregnancy >=12 weeks 300 mcg should be givenSite of InjectionAnti D-immunoglobulin is best given intramuscularly into the deltoid muscle as injections into the gluteal region often reach the subcutaneous tissues and absorption may be delayed.Antepartum prophyllaxis in Rh negative motherIt is given at 28 weeks in all Rh negative pregnant females with indirect Coombs test negative. Dose =300mg=1500I/U (single injection).