Anti-D prophylaxis should be given in all of the following conditions except :

Ans. is c i.e. Intrauterine transfusion at 28 weeks Rh anti D immunoglobulin (IgG) is given to unimmunized Rh negative mothers with Rh positive fetus to prevent active immunization and formation of antibodies against fetal RBC's. The Anti D binds to antigen sites on the fetal red cells so that these cells do not mount an immune response, provided the baby is Rh negative and direct coombs test done on baby is negative. If mother's IUT is positive or fetus has positive direct coombs test, it means mother is already immunised. In such cases their is no point in giving anti D. Dose : * Ideally amount of Anti D should be calculated according to the volume of fetomaternal bleed by doing a Kleihauer test. Generally : - Gestational age < 12 weeks - dose is 5Oug - Beyond 12 weeks - dose is 300ug Antepaum prophylaxis : At 28 weeks gestation in a Rh negative patient : Indirect coombs test is done and if antibodies are not detected i.e. patient is unimmunized, Anti D 300ug is given as antepaum prophylaxis. To know the exact amount of feto maternal bleed Kleihauer Betke test is done 300 pg of Anti D will neutralize about 30 ml of feto maternal bleed (i.e. approximately 15 ml of fetal cell).