title: Association of ABO incompatibility with red blood cell indices of cord blood unit.
abstract: BACKGROUND
  Maternal-fetal ABO incompatibility is one of the causes of neonatal hyperbilirubinemia. We postulate that hemoglobin (Hb), hematocrit (Hct), and red blood cell (RBC) values for cord blood units (CBUs) are lower and erythroblast values higher for maternal-fetal ABO incompatible dyads than for compatible dyads.
  
  
  OBJECTIVE
  We investigated the relationship between Hb, Hct, RBC, and erythroblast CBU values and maternal-fetal ABO blood type compatibility.
  
  
  METHODS
  Mothers having blood group O who gave birth to infants with blood group A, B, or AB were classified as Group I. According to baby's blood group, the members of Group I were further divided into AO (baby group A, mother group O), BO (baby group B, mother group O), and ABO (baby group AB, mother group O) subgroups. Mothers having blood group A who gave birth to infants with blood group B or AB and mothers having blood group B who gave birth to infants with blood group A or AB were classified as Group II. All other maternal-fetal blood type pairs were considered ABO compatible and were classified as Group III. We compared mean Hb, Hct, RBC, and erythroblast values for the infants' CBUs among these three groups including the subgroups of Group I.
  
  
  RESULTS
  Group I had lower mean Hb, Hct, and RBC values than Group II and Group III (both p < 0.001). Although the mean Hb, Hct, and RBC values for Group II were lower than for Group III, the difference was not statistically significant. Mean Hb and RBC for the AO group were higher and nucleated RBC (nRBC) ratios were lower than for the BO group; however, these differences were also not statistically significant. Interestingly, the mean Hct value of the BO group was significantly lower than that of the AO group (p = 0.04).
  
  
  CONCLUSIONS
  Group A or B neonates with a group O mother have lower mean Hb, Hct, and RBC values for CBUs than other neonates. The role of RBC indices in predicting neonatal hemolytic hyperbilirubinemia remains unclear and further studies are needed to identify the possible clinical association.
authors.affiliation: Department of Pediatrics, Buddhist Tzu-Chi General Hospital, Hualien, Taiwan.
authors.forename: Shu-Huey
authors.initials: SH
authors.lastname: Chen
authors.forename: Marie
authors.initials: M
authors.lastname: Lin
authors.forename: Kuo-Liang
authors.initials: KL
authors.lastname: Yang
authors.forename: Teng-Yi
authors.initials: TY
authors.lastname: Lin
authors.forename: His-Hsiu
authors.initials: HH
authors.lastname: Tsai
authors.forename: Shang-Hsien
authors.initials: SH
authors.lastname: Yang
authors.forename: Yu-Hsun
authors.initials: YH
authors.lastname: Chang
authors.forename: Yi-Feng
authors.initials: YF
authors.lastname: Wu
authors.forename: Tso-Fu
authors.initials: TF
authors.lastname: Wang
mesh_terms: D000017:ABO Blood-Group System / Q000276:immunology*; D001787:Blood Group Incompatibility / Q000097:blood*; D004909:Erythrocyte Indices; D005312:Fetal Blood / Q000276:immunology*; D006400:Hematocrit; D006454:Hemoglobins / Q000032:analysis; D006801:Humans; D007231:Infant, Newborn
chemical_list: D000017:ABO Blood-Group System; D006454:Hemoglobins