Rho(D) immune globulin shortage and fetal Rh(D) screening with cell-free DNA.

Abstract

Purpose of review: Despite the availability of Rh(D) immune globulin (RhIg) to prevent alloimmunization in Rh(D)-negative pregnant patients, anti-Rh(D) alloimmunization remains a prevalent cause of hemolytic disease of the fetus and newborn (HDFN). Recent RhIg shortages have caused clinicians and professional societies to identify methods to prioritize RhIg administration. New cell-free DNA (cfDNA) tests to predict fetal red blood cell antigen genotypes have been proposed as an option to prioritize the administration of RhIg to Rh(D)-negative pregnant people.

Recent findings: Commercial laboratories offer fetal Rh(D) genotype testing as part of cfDNA screening for fetal aneuploidy. Studies indicate that these tests have a high sensitivity and specificity for the detection of fetal Rh(D) status. Considering the current RhIg shortage, the American College of Obstetricians & Gynecologists (ACOG) suggests that utilizing cfDNA tests to determine fetal Rh(D) status is a reasonable approach to prioritize RhIg administration when supply is limited.

Summary: cfDNA screening for fetal Rh(D) status is a reasonable approach to triage the administration of RhIg in the setting of the current RhIg shortage. Utilization of cfDNA screening for fetal Rh(D) and other red blood cell antigen status is likely to increase in routine care. Research, professional society guidance, and education are necessary to ensure well tolerated and equitable utilization.