Objective: To examine whether literature supports the use of Rh immune globulin in Rh-negative women with first trimester spontaneous abortions to prevent maternal sensitization to the fetal Rh antigen and subsequent fetal morbidity and mortality.
Methods: We searched MEDLINE (1966-2005), the Cochrane Central Register of Controlled Trials, EMBASE (1990 to 2005), and the reference sections of the articles found. The search is considered updated to December of 2005. Search terms included vaginal bleeding, Rh negative, Rh immune globulin, RhoGAM, isoimmunization, sensitization, first trimester pregnancy, threatened, and spontaneous abortion.
Results: The evidence to support the use of Rh immune globulin for a diagnosis of first trimester spontaneous abortion is minimal. There is a paucity of well-designed research that examines maternal sensitization or hemolytic disease of the newborn as an outcome in patients receiving, versus not receiving, Rh immune globulin in first trimester bleeding. There is significant evidence to demonstrate fetomaternal hemorrhage in first trimester spontaneous abortions; yet, no studies demonstrate subsequent maternal sensitization or development hemolytic disease in the fetus as a result of this hemorrhage.
Conclusion: In summary, there is minimal evidence that administering Rh immune globulin for first trimester vaginal bleeding prevents maternal sensitization or development of hemolytic disease of the newborn. The practice of administering Rh immune globulin to Rh-negative women with a first trimester spontaneous abortion is based on expert opinion and extrapolation from experience with fetomaternal hemorrhage in late pregnancy. Its use for first trimester bleeding is not evidence-based.