title: Incidence and risk patterns of venous thromboembolism in pregnancy and puerperium--a register-based case-control study.
abstract: OBJECTIVE
  This study was undertaken to estimate the incidence of venous thromboembolism in pregnancy and puerperium and to identify risk factors for pregnancy-related venous thromboembolism.
  
  
  METHODS
  A register-based case-control study with 613,232 pregnancies from 1990-2003 in 11 Norwegian counties. Medical records for eligible cases were revisited and relevant medical data were transferred to a specific case-report form. The diagnosis of venous thromboembolism was based on strict criteria. Data were analyzed by chi2 test and forward stepwise logistic regression.
  
  
  RESULTS
  In total, 615 cases were detected. The incidence of venous thromboembolism was 1 per 1000 pregnancies. The ante- and postnatal incidences were quite similar. Antenatal risk factors were assisted reproduction, gestational diabetes, age older than 35 years, multiple pregnancies, and primi-parity. Postnatal risk factors were cesarean section, preeclampsia, assisted reproduction, abruptio placenta, and placenta previa.
  
  
  CONCLUSIONS
  We found different ante- and postnatal risk patterns. Assisted reproduction and gestational diabetes were significant antenatal risk factors; whereas cesarean section and preeclampsia were strong postnatal risk factors.
authors.affiliation: Department of Obstetrics and Gynecology, Ulleval University Hospital Trust, Oslo, Norway. anneflem.jacobsen@ulleval.no
authors.forename: Anne Flem
authors.initials: AF
authors.lastname: Jacobsen
authors.forename: Finn Egil
authors.initials: FE
authors.lastname: Skjeldestad
authors.forename: Per Morten
authors.initials: PM
authors.lastname: Sandset
mesh_terms: D000293:Adolescent; D000328:Adult; D016022:Case-Control Studies; D005260:Female; D006801:Humans; D015994:Incidence; D008875:Middle Aged; D009664:Norway / Q000453:epidemiology; D011247:Pregnancy; D011249:Pregnancy Complications, Cardiovascular / Q000453:epidemiology* / Q000209:etiology / Q000517:prevention & control; D011295:Prenatal Care; D011644:Puerperal Disorders / Q000453:epidemiology* / Q000209:etiology / Q000517:prevention & control; D012042:Registries; D012189:Retrospective Studies; D012307:Risk Factors; D054556:Venous Thromboembolism / Q000453:epidemiology* / Q000209:etiology / Q000517:prevention & control