title: A systematic review of the association between factor V Leiden or prothrombin gene variant and intrauterine growth restriction.
abstract: OBJECTIVE
  The purpose of this study was to conduct a systematic review of the literature of studies that examined the association between factor V Leiden and/or prothrombin gene variant and intrauterine growth restriction.
  
  
  METHODS
  This systematic review of studies assesses the association between factor V Leiden and/or prothrombin gene variant and intrauterine growth restriction.
  
  
  RESULTS
  Ten case-control studies fulfilled the selection criteria for inclusion in the meta-analysis. There was a significant association between factor V Leiden and intrauterine growth restriction (odds ratio, 2.7; 95% CI, 1.3-5.5) and prothrombin gene variant and intrauterine growth restriction (odds ratio, 2.5; 95% CI, 1.3-5.0). Five cohort studies were identified in the systematic review; 3 studies were prospective (2 full publications), and 2 studies were retrospective (1 full publication). Combining the 2 full publication prospective studies yields a summary relative risk of 0.99 (95% CI, 0.5-1.9).
  
  
  CONCLUSIONS
  This meta-analysis of case-control studies suggests that the factor V Leiden and prothrombin gene variant both confer an increased risk of giving birth to an intrauterine growth restricted infant, although this may be driven by small, poor-quality studies that demonstrated extreme associations. Large well-conducted prospective cohort studies are required to determine definitively whether an association between thrombophilia and intrauterine growth restriction is present.
authors.affiliation: University of Ottawa, Ottawa, Ontario, Canada.
authors.forename: Heather E A
authors.initials: HE
authors.lastname: Howley
authors.forename: Mark
authors.initials: M
authors.lastname: Walker
authors.forename: Marc A
authors.initials: MA
authors.lastname: Rodger
mesh_terms: D016022:Case-Control Studies; D005165:Factor V / Q000235:genetics*; D005260:Female; D005317:Fetal Growth Retardation / Q000235:genetics*; D014644:Genetic Variation; D006801:Humans; D011247:Pregnancy; D011516:Prothrombin / Q000235:genetics*
chemical_list: C095381:factor V Leiden; D005165:Factor V; D011516:Prothrombin