It is most frequent in Rh(D) negative women in general. Female patients have significantly higher frequency of Rh negative, particularly O negative. This study will help in making public health policies. https://www.researchgate.net/publication/323666035_Distribution_of_ABO_Blood_Groups_and_Rhesus_Factor_In_ss-Thalassemia_Patients_at_Thalassemia_Care_Center_NawabShah_Pakistan The irregular antibody production for β-thalassemic children with long-term transfusion may have some relevance with Rh factor genotypes and thalassemia genetic mutations. This study possesses a certain significance for effective prevention of RBC alloimmune response of β-thalassemia children and improvement of efficacy and safety of clinical transfasion blood. https://www.ncbi.nlm.nih.gov/pubmed/26708889