title: Platelet antibodies and fetal growth: maternal antibodies against fetal platelet antigen 1a are strongly associated with reduced birthweight in boys.
abstract: OBJECTIVE
  To assess whether maternal HPA 1a alloimmunization is associated with birthweight.
  
  
  METHODS
  A retrospective observational cohort study.
  
  
  METHODS
  The national reference laboratory for clinical platelet immunology at a university hospital.
  
  
  METHODS
  165 HPA 1a incompatible pregnancies identified from a recent screening study of 100 448 women (124 pregnancies) and the national reference laboratory for clinical platelet immunology (41 pregnancies).
  
  
  METHODS
  A linear mixed model analysis was used to assess whether maternal anti-HPA 1a antibodies were associated with birthweight. A generalized linear model was used to assess maternal anti-HPA 1a antibodies as risk factor for small-for-gestational age neonates. Both models were adjusted for gestational age at time of delivery, maternal age, parity, smoking habits during pregnancy, preeclampsia, diabetes mellitus and fetal sex. MAIN OUTCOME MEASURES. Maternal anti-HPA 1a antibody as risk factor of reduced birthweight and small-for-gestational age neonates.
  
  
  RESULTS
  The level of maternal anti-HPA 1a antibodies was significantly associated with birthweight and risk of small-for-gestational age neonates after correcting for confounding variables (p<0.001). However, this association was only significant for boys. When the mother had high levels of anti-HPA 1a antibodies during pregnancy, the adjusted mean birthweight in boys was 530g lower compared with anti-HPA 1a antibody negative pregnancies (p<0.001).
  
  
  CONCLUSIONS
  A linear relation between maternal anti-HPA 1a antibody levels and reduced birthweight in boys was demonstrated. Reduced birthweight should be considered a possible complication of fetal and neonatal alloimmune thrombocytopenia.
authors: Laboratory Medicine.
authors: Heidi
authors: H
authors: Tiller
authors: Laboratory Medicine.
authors: Mette Kjaer
authors: MK
authors: Killie
authors: Laboratory Medicine.|Division of Immunology, Institute of Medical Biology.
authors: Anne
authors: A
authors: Husebekk
authors: Laboratory Medicine.|Division of Immunology, Institute of Medical Biology.
authors: Bjørn
authors: B
authors: Skogen
authors: Division of Transfusion Medicine, St. Michael's Hospital, Toronto, Canada.|Canadian Blood Services and Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, Canada.
authors: Heyu
authors: H
authors: Ni
authors: Immunology and Transfusion Medicine, Oslo University Hospital, Oslo, Norway.|Institute of Clinical Medicine, University of Oslo, Oslo, Norway.
authors: Jens
authors: J
authors: Kjeldsen-Kragh
authors: Department of Obstetrics and Gynecology, University Hospital of North Norway, Tromsø, Norway.|Department of Obstetrics and Gynecology, Institute of Clinical Medicine, University of Tromsø, Tromsø, Norway.
authors: Pål
authors: P
authors: Øian
mesh_terms: D000328:Adult; D016824:Antigens, Human Platelet / Q000276:immunology*; D001724:Birth Weight; D001787:Blood Group Incompatibility / Q000097:blood / Q000276:immunology*; D015331:Cohort Studies; D005260:Female; D006801:Humans; D007230:Infant, Low Birth Weight / Q000276:immunology; D007231:Infant, Newborn; D007236:Infant, Small for Gestational Age / Q000276:immunology*; D039661:Integrin beta3; D007518:Isoantibodies / Q000097:blood*; D016014:Linear Models; D016015:Logistic Models; D008297:Male; D011247:Pregnancy; D011250:Pregnancy Complications, Hematologic / Q000097:blood / Q000276:immunology*; D012189:Retrospective Studies; D012307:Risk Factors; D012737:Sex Factors; D054098:Thrombocytopenia, Neonatal Alloimmune / Q000097:blood / Q000276:immunology*
chemical_list: D016824:Antigens, Human Platelet; C061248:ITGB3 protein, human; D039661:Integrin beta3; D007518:Isoantibodies