title: Risk factors for the presence of non-rhesus D red blood cell antibodies in pregnancy.
abstract: OBJECTIVE
  To identify risk factors for the presence of non-rhesus D (RhD) red blood cell (RBC) antibodies in pregnancy. To generate evidence for subgroup RBC antibody screening and for primary prevention by extended matching of transfusions in women <45 years.
  
  
  METHODS
  Case-control study.
  
  
  METHODS
  Nationwide evaluation of screening programme for non-RhD RBC antibodies.
  
  
  METHODS
  
  
  
  METHODS
  consecutive pregnancies (n=900) with non-RhD immunisation identified from 1 September 2002 to 1 June 2003 and 1 October 2003 to 1 July 2004; controls (n=968): matched for obstetric caregiver and gestational age.
  
  
  METHODS
  Data collection from the medical records and/or from the respondents by a structured phone interview.
  
  
  METHODS
  Significant risk factors for non-RhD immunisation in multivariate analysis.
  
  
  RESULTS
  Significant independent risk factors: history of RBC transfusion (OR 16.7; 95% CI: 11.4-24.6), parity (para-1 versus para-0: OR 1.3; 95% CI: 1.0-1.7; para-2 versus para-0: OR 1.4; 95% CI: 1.0-2.0; para >2 versus para-0: OR 3.2; 95% CI: 1.8-5.8), haematological disease (OR 2.1; 95% CI: 1.0-4.2), history of major surgery (OR 1.4; 95% CI: 1.1-1.8). For the clinically most important antibodies, anti-K, anti-c and other Rh-nonD-antibodies RBC transfusion was the most important risk factor, especially for anti-K (OR 96.4; 95%-CI: 56.6-164.1); 83% of the K-sensitised women had a history of RBC transfusion. Pregnancy-related risk factors were a prior male child (OR 1.7; 95% CI: 1.2-2.3) and caesarean section (OR 1.7; 95% CI: 1.1-2.7).
  
  
  CONCLUSIONS
  RBC transfusion is by far the most important independent risk factor for non-RhD immunisation in pregnancy, followed by parity, major surgery and haematological disease. Pregnancy-related risk factors are a prior male child and caesarean section. Subgroup screening for RBC antibodies, with exclusion of RhD-positive para-0 without clinical risk factors, is to be considered. This approach will be equally sensitive in detecting severe Haemolytic Disease of the Fetus and Newborn compared with the present RBC antibody screening programme without preselection. Primary prevention by extending preventive matching of transfusions in women younger than 45 will prevent more than 50% of pregnancy immunisations.
authors.affiliation: Sanquin Research, Amsterdam, and Landsteiner Laboratory, Academic Medical Centre, University of Amsterdam, Department of Experimental Immunohematology, Amsterdam, The Netherlands.
authors.forename: J M
authors.initials: JM
authors.lastname: Koelewijn
authors.forename: T G M
authors.initials: TG
authors.lastname: Vrijkotte
authors.forename: M
authors.initials: M
authors.lastname: de Haas
authors.forename: C E
authors.initials: CE
authors.lastname: van der Schoot
authors.forename: G J
authors.initials: GJ
authors.lastname: Bonsel
mesh_terms: D000328:Adult; D001788:Blood Grouping and Crossmatching; D001803:Blood Transfusion; D016022:Case-Control Studies; D002585:Cesarean Section; D004912:Erythrocytes / Q000276:immunology*; D005260:Female; D006402:Hematologic Diseases; D006801:Humans; D007155:Immunologic Factors / Q000097:blood*; D007518:Isoantibodies / Q000097:blood*; D015999:Multivariate Analysis; D016017:Odds Ratio; D010298:Parity / Q000276:immunology; D011183:Postoperative Complications / Q000276:immunology / Q000601:surgery; D011247:Pregnancy; D011250:Pregnancy Complications, Hematologic / Q000097:blood*; D012203:Rh Isoimmunization / Q000097:blood*; D012204:Rh-Hr Blood-Group System; D012307:Risk Factors
chemical_list: D007155:Immunologic Factors; D007518:Isoantibodies; D012204:Rh-Hr Blood-Group System