Can We Safely Stop Administering Anti-D Immune Globulin to First Trimester Rh-Negative Mothers Undergoing Abortion? A Systematic Review and Meta-Analysis

Abstract

Introduction: Fetal red blood cells can express the D-antigen as early as 52 days after the last menstrual period. However, there is no convincing evidence for the benefit of using anti-D immune globulin (RhIG) in the first trimester. The aim of the current review is therefore to determine whether administration of RhIG to women undergoing first trimester spontaneous or induced abortions prevents subsequent sensitization. Methods: We searched Medline, Embase.com, Cochrane Central Register of Controlled Trials (CCRCT) via EBM Reviews (Ovid), ClinicalTrials.gov (www.clinicaltrials.gov) and the WHO International Clinical Trials Registry Platform (ICTRP) (www.who.int/ictrp/search/en). Two reviewers performed the study selection, critical appraisal, and data extraction independently. Quality of evidence for major outcomes was assessed using the Grading of Recommendations, Assessment, development, and evaluation (GRADE). Results: Four studies met the inclusion criteria with total of 444 participants. The fixed effect meta-analysis showed that there is 0.41 times less antibody formation in women who received RhIG compared to those who did not receive (OR = 0.41, CI, 0.05-3.66, P-value 0.43). Women who took anti-D were also 0.75 times less likely to be sensitized in subsequent pregnancy compared to women who received RhIG (OR = 0.75, CI 0.07-8.42, P-value 0.82). However, none of the studies reported on Increased fetal surveillance or fetal transfusion in subsequent pregnancy, neonatal morbidity, maternal adverse event and cost of treatment. Conclusions: The evidence of RhIG provision following first trimester abortion to prevent antibody formation and sensitization in a subsequent pregnancy is statistically insignificant and very low quality. The practice of administering RhIG after first trimester abortion is based on expert opinion and largely extrapolated from fetomaternal hemorrhage in late pregnancy. However, the evidence indicates that the fetomataernal hemorrhage in the first trimester is not enough to cause sensitization. Therefore, the recommendation to administer RhIG in the first trimester should depend on effectiveness, resource availability, cost, values, preferences, equity, acceptability and feasibility of RhIG provision.