This technique is now used in several countries in Europe to identify which RhD-negative women are carrying an RhD-positive fetus [7,8,9], and these countries have changed their routine to targeted antenatal RhD prophylaxis, i.e., hyperimmune anti-D IgG is only administered to RhD-negative women carrying an RhD-positive fetus. The gene discussed is RHD; the disease is rheumatic heart disease.