A total of 1579 Rh-negative women who were delivered of Rh-positive babies received Rh0(D) immune globulin (human) or Rh0(D) immune globulin (human) PPF to protect them against sensitization by the Rh factor. Follow-up serologic evaluations were carried out 6 weeks, 4 months, and 6 months following delivery. Efficacy of treatment, as demonstrated by antibody titer data after 6 months, was 99.5% in women with an ABO compatible pregnancy and 100% in other women.