Although there are few studies on the use of RhoGAM for first-trimester miscarriages, most physicians will recommend that an Rh-negative patient receive RhoGAM after a first-trimester miscarriage, ectopic pregnancy, or other pregnancy loss due to the theoretical risk of sensitization. Although the risk of sensitization after a miscarriage is relatively small, it has been documented and it’s thought that the potential benefits outweigh the risks. RhoGAM protects against Rh-incompatibility that could affect future pregnancies and cause hemolytic disease of the newborn. It needs to be given within 72 hours of the onset of bleeding in order to be effective.
Until there’s further evidence to the contrary, it’s probably best to err on the side of caution and administer Rhogam if first-trimester bleeding/miscarriage occurs. A dose of 120 µg should be sufficient in these instances.