title: Preconception venous thromboembolism and placenta-mediated pregnancy complications.
abstract: BACKGROUND
  Placenta-mediated complications are leading causes of maternal and fetal morbidity and mortality. We hypothesized that a preconception history of venous thromboembolism (VTE) is associated with increased risk of placenta-mediated pregnancy complications.
  
  
  METHODS
  A nationwide population-based cohort study of all singleton pregnancies leading to delivery from 1997 to 2012 (n = 964 967). We obtained data on placenta-mediated pregnancy complications from the Danish Medical Birth Registry and data on VTE before pregnancy from the Danish National Patient Registry. We computed absolute risks, crude and adjusted risk differences (RDs) using a binomial regression model, and crude and adjusted risk ratios (RRs) from a modified Poisson regression model.
  
  
  RESULTS
  Overall, 1419 women had a preconception history of VTE, while 578 112 did not. Preeclampsia occurred in 4.2% of pregnancies in the VTE group and in 2.7% of pregnancies in a comparison cohort (adjusted RD = 1.3%, 95% confidence interval (CI) 0.6-2.0%; adjusted RR = 1.5, 95% CI 1.3-1.8). Stillbirth occurred in 0.7% of pregnancies in the VTE group and in 0.4% of pregnancies in the comparison cohort (adjusted RD = 0.3%, 95% CI 0.02-0.6%; adjusted RR = 1.8, 95% CI 1.1-3.0). Placental abruption occurred in 0.8% of pregnancies in the VTE group and in 0.5% of pregnancies in the comparison cohort (adjusted RD = 0.3%, 95% CI - 0.05-0.6%; adjusted RR = 1.6, 95% CI 1.1-2.4). Small-for-gestational-age infants accounted for 10.9% of live births in the VTE group and 9.8% of live births in the comparison cohort (adjusted RD = 0.6%, 95% CI - 0.5-1.7%; adjusted RR = 1.1, 95% CI 0.9-1.3).
  
  
  CONCLUSIONS
  Women with a history of VTE were at increased risk of placenta-mediated complications.
authors.affiliation: Department of Clinical Epidemiology, Center for Haemophilia and Thrombosis, Aarhus University Hospital, Aarhus, Denmark.|Department of Clinical Biochemistry, Center for Haemophilia and Thrombosis, Aarhus University Hospital, Aarhus, Denmark.
authors.forename: A T
authors.initials: AT
authors.lastname: Hansen
authors.affiliation: Department of Clinical Epidemiology, Center for Haemophilia and Thrombosis, Aarhus University Hospital, Aarhus, Denmark.
authors.forename: M
authors.initials: M
authors.lastname: Schmidt
authors.affiliation: Department of Clinical Epidemiology, Center for Haemophilia and Thrombosis, Aarhus University Hospital, Aarhus, Denmark.
authors.forename: E
authors.initials: E
authors.lastname: Horváth-Puhó
authors.affiliation: Department of Clinical Epidemiology, Center for Haemophilia and Thrombosis, Aarhus University Hospital, Aarhus, Denmark.
authors.forename: L
authors.initials: L
authors.lastname: Pedersen
authors.affiliation: Department of Clinical Epidemiology, Center for Haemophilia and Thrombosis, Aarhus University Hospital, Aarhus, Denmark.|RTI Health Solutions, Research Triangle Institute, Research Triangle Park, NC, USA.
authors.forename: K J
authors.initials: KJ
authors.lastname: Rothman
authors.affiliation: Department of Clinical Biochemistry, Center for Haemophilia and Thrombosis, Aarhus University Hospital, Aarhus, Denmark.
authors.forename: A M
authors.initials: AM
authors.lastname: Hvas
authors.affiliation: Department of Clinical Epidemiology, Center for Haemophilia and Thrombosis, Aarhus University Hospital, Aarhus, Denmark.
authors.forename: H T
authors.initials: HT
authors.lastname: Sørensen
mesh_terms: D000037:Abruptio Placentae / Q000453:epidemiology*; D000293:Adolescent; D000328:Adult; D002648:Child; D015331:Cohort Studies; D015897:Comorbidity; D003718:Denmark / Q000453:epidemiology; D004198:Disease Susceptibility; D005260:Female; D005317:Fetal Growth Retardation / Q000453:epidemiology*; D006801:Humans; D006973:Hypertension / Q000453:epidemiology; D007231:Infant, Newborn; D007236:Infant, Small for Gestational Age; D007674:Kidney Diseases / Q000453:epidemiology; D008297:Male; D008423:Maternal Age; D010298:Parity; D016012:Poisson Distribution; D011225:Pre-Eclampsia / Q000453:epidemiology*; D011247:Pregnancy; D011254:Pregnancy in Diabetics / Q000453:epidemiology; D012008:Recurrence; D012042:Registries; D012189:Retrospective Studies; D012306:Risk; D012907:Smoking / Q000453:epidemiology; D050497:Stillbirth / Q000453:epidemiology*; D054556:Venous Thromboembolism / Q000453:epidemiology*; D055815:Young Adult
keywords: abruptio placentae; cohort study; infant, small-for-gestational age; preeclampsia; stillbirth; venous thromboembolism