Antenatal Rh Immune Globulin (RhIG) dose, timing, and indications following selected procedures and complications: a scoping review.

OBJECTIVE Studies addressing RhD alloimmunization following antenatal procedures and complications are limited, and practice of RhIG administration following these events is variable. Our objective was to assess evidence for RhIG efficacy for RhD negative pregnancies following selected antenatal events.

DATA SOURCES Literature was sourced from databases including MEDLINE, EMBASE, Cochrane Evidence Based Medical (EBM) Reviews, and Cumulative Index to Nursing and Allied Health Literature (CINAHL) (1946 to August 2024).

STUDY SELECTION Studies included those focused on RhIG effectiveness following antenatal procedures or complications.

DATA EXTRACTION AND SYNTHESIS Thirty-one papers focused on alloimmunization risk and RhIG administration in the setting of antenatal procedures or events including chorionic villus sampling (CVS) (5), amniocentesis (ACS) (15), external cephalic version (ECV) (5), ectopic pregnancy (EP) (1), trauma (2), placenta previa (PP) and placental abruption (PA) (3). Most were retrospective or prospective observational trials conducted prior to 1995, and were variable in size, quality, methodology, and outcome parameters. Papers evaluated alloimmunization (11) or fetal maternal hemorrhage (FMH) (21) as a surrogate outcome and found that all interventions and/or complications increased risk of RhD alloimmunization.

CONCLUSION The available literature supports RhIG prophylaxis for the listed procedures and complications. Data is limited by low methodologic quality, is frequently based on surrogate markers of alloimmunization, and reflects outcomes following antiquated procedures and techniques. With limited RhIG supply and a cautious approach to blood product administration, the general support for RhIG prophylaxis should be re-evaluated with high quality trials.