title: Classification of stillbirths and risk factors by cause of death--a case-control study.
abstract: OBJECTIVE
  To investigate risk factors for stillbirths by cause, using the Causes of Death and Associated Conditions (CODAC) classification system for perinatal deaths.
  
  
  METHODS
  Case-control study.
  
  
  METHODS
  Two university hospitals in Oslo, Norway, January 1990 through December 2003.
  
  
  METHODS
  Women with stillbirth after 22 gestational weeks (n = 377) and controls with live births (n = 1 215), and a subsample of 105 cases and 262 controls.
  
  
  METHODS
  Socio-demographic, clinical and thrombophilic risk factors for stillbirths were assessed by cause of death in univariate and multivariable logistic regression analyses. Stillbirths were classified according to CODAC based on information from medical records and validated placenta histology.
  
  
  METHODS
  Causes of stillbirths in percentages, prevalence, odds ratios and adjusted odds ratios for potential risk factors.
  
  
  RESULTS
  Approximately half of the women (n = 190) had placental and 19.4% (n = 73) unknown cause of stillbirth. Placental-associated conditions were registered in 18% (n = 68) of cases with a non-placental or an unknown cause. Smoking and small-for-gestational age were more prevalent in all causal groups, compared with controls, whereas twin pregnancy, hypertension and diabetes were more prevalent only among women with placental and unknown causes of stillbirth. The F2rs179963 polymorphism and combined thrombophilia were significant risk factors for stillbirth with placental causes and antiphospholipid antibodies for stillbirth with non-placental causes.
  
  
  CONCLUSIONS
  Two-thirds of all stillbirths (68%) were caused by or associated with placental pathology. Risk factors differed somewhat according to cause, apart from smoking and small-for-gestational age, which were significant risk factors across the causal groups.
authors.affiliation: Department of Hematology, Oslo University Hospital Ullevål, Oslo. linda_bjork_helgadottir@hotmail.com
authors.forename: Linda Björk
authors.initials: LB
authors.lastname: Helgadóttir
authors.forename: Gitta
authors.initials: G
authors.lastname: Turowski
authors.forename: Finn Egil
authors.initials: FE
authors.lastname: Skjeldestad
authors.forename: Anne Flem
authors.initials: AF
authors.lastname: Jacobsen
authors.forename: Per Morten
authors.initials: PM
authors.lastname: Sandset
authors.forename: Borghild
authors.initials: B
authors.lastname: Roald
authors.forename: Eva-Marie
authors.initials: EM
authors.lastname: Jacobsen
mesh_terms: D000328:Adult; D017152:Antibodies, Antiphospholipid / Q000097:blood; D001724:Birth Weight; D016022:Case-Control Studies; D002423:Cause of Death; D016640:Diabetes, Gestational / Q000453:epidemiology; D005260:Female; D005313:Fetal Death / Q000453:epidemiology* / Q000235:genetics; D005865:Gestational Age; D006801:Humans; D006973:Hypertension / Q000453:epidemiology; D016015:Logistic Models; D015999:Multivariate Analysis; D009664:Norway / Q000453:epidemiology; D016017:Odds Ratio; D010922:Placenta Diseases / Q000453:epidemiology; D011110:Polymorphism, Genetic; D011247:Pregnancy; D011254:Pregnancy in Diabetics / Q000453:epidemiology; D059285:Pregnancy, Twin; D015995:Prevalence; D011516:Prothrombin / Q000235:genetics; D012189:Retrospective Studies; D012307:Risk Factors; D012907:Smoking / Q000453:epidemiology; D050497:Stillbirth / Q000453:epidemiology* / Q000235:genetics; D019851:Thrombophilia / Q000453:epidemiology
chemical_list: D017152:Antibodies, Antiphospholipid; D011516:Prothrombin