title: Venous thromboembolism in relation to in vitro fertilization: an approach to determining the incidence and increase in risk in successful cycles.
abstract: OBJECTIVE
  To determine the incidence and the increase in risk of venous thromboembolism (VTE) in relation to IVF and ovarian hyperstimulation syndrome (OHSS) in successful cycles.
  
  
  METHODS
  Cohort study.
  
  
  METHODS
  Population based.
  
  
  METHODS
  All deliveries (n = 964,532) in Sweden during a 10-year period (1999-2008).
  
  
  METHODS
  Comparison of VTEs among those with and without IVF. The National Birth Registry was cross-matched with both the National Discharge Registry and the National IVF Registry. Logistic regression analysis was used to determine odds ratios and 95% confidence intervals.
  
  
  METHODS
  Risk of first trimester VTE.
  
  
  RESULTS
  The incidence of first-trimester VTE in relation to IVF was 0.2%, representing a 10-fold increase as compared with the background population. The 6% to 7% of IVF pregnancies that were complicated by OHSS showed a 100-fold increased risk of VTE, as opposed to the fivefold increased risk seen in the absence of OHSS. The VTEs in conjunction with IVF were diagnosed at a mean gestational age of 62 days; there was no increased risk of VTE related to frozen embryo replacement cycles or IVF after the first trimester.
  
  
  CONCLUSIONS
  Treating women with OHSS with low-molecular-weight heparin thromboprophylaxis during the first trimester and treating cases at high-risk for OHSS with frozen embryo replacement is likely to lower the risk of VTE.
authors: Department of Fertility, Clintec, Karolinska University Hospital, Huddinge, Stockholm, Sweden.
authors: Karin
authors: K
authors: Rova
authors: Henrik
authors: H
authors: Passmark
authors: Pelle G
authors: PG
authors: Lindqvist
mesh_terms: D000328:Adult; D000925:Anticoagulants / Q000627:therapeutic use; D015331:Cohort Studies; D005260:Female; D005307:Fertilization in Vitro / Q000009:adverse effects* / Q000706:statistics & numerical data*; D006495:Heparin, Low-Molecular-Weight / Q000627:therapeutic use; D006801:Humans; D015994:Incidence; D007231:Infant, Newborn; D008297:Male; D011247:Pregnancy; D011250:Pregnancy Complications, Hematologic / Q000188:drug therapy / Q000453:epidemiology*; D011256:Pregnancy Outcome / Q000453:epidemiology*; D011261:Pregnancy Trimester, First; D012042:Registries / Q000706:statistics & numerical data; D012307:Risk Factors; D013548:Sweden / Q000453:epidemiology; D054556:Venous Thromboembolism / Q000188:drug therapy / Q000453:epidemiology*; D055815:Young Adult
chemical_list: D000925:Anticoagulants; D006495:Heparin, Low-Molecular-Weight