RESUMEN
【Objective】 To analyze the causes of a case of hemolytic disease of the fetus and newborn (HDFN),and investigate the genetic background of maternal Rh deletion D--formation. 【Methods】 Blood samples of maternal and fetus were collected, and ABO blood typing, Rh blood typing, antibody screening and identification test were performed to explore the blood group serological characteristics of Rh deletion type D--, and Rh gene sequence was performed on parturient. 【Results】 The maternal blood group was identified to be O type, D--, and the anti-Hr0 antibody against Rh high-frequency antigen was suspected to be caused by multiple pregnancies which passes through the placental barrier and enable fetus to obtain anti Hr0 antibody, leading to HDFN, with genetic testing result as RH RHCE* Ce/RHCE* Ce. 【Conclusion】 In-depth research on the formation mechanism of Rh D-- in parturient should be conducted to provide clinical value for HDFN blood exchange treatment and blood transfusion in special blood group population.