title: Maternal and pregnancy characteristics affect plasma fibrin monomer complexes and D-dimer reference ranges for venous thromboembolism in pregnancy.
abstract: D-dimers have a high negative predictive value for excluding venous thromboembolism outside of pregnancy but the use in pregnancy remains controversial. A higher cut-off value has been proposed in pregnancy due to a continuous increase across gestation. Fibrin monomer complexes have been considered as an alternative diagnostic tool for exclusion of venous thromboembolism in pregnancy due to their different behavior.
  
  
  
  We sought to establish normal values of fibrin monomer complexes and D-dimer as a diagnostic tool for the exclusion of venous thromboembolism in pregnancy and examine the effect of maternal and obstetric factors on these markers.
  
  
  
  Plasma D-dimer and fibrin monomer complexes were measured by quantitative immunoturbidimetry in 2870 women with singleton pregnancies attending their routine first-trimester hospital visit in a prospective screening study for adverse obstetric outcome. Multiple regression analysis was used to determine maternal characteristics and obstetric factors affecting the plasma concentrations and converting these into multiple of the median values after adjusting for significant maternal and obstetric characteristics.
  
  
  
  Plasma fibrin monomer complexes increased with maternal weight and were lower in women with a history of cocaine abuse and chronic hypertension. D-dimers increased with gestational age and maternal weight and were higher in sickle cell carriers and in women of African and South Asian racial origin compared to Caucasians.
  
  
  
  Fibrin monomer complexes and D-dimers are affected by maternal and obstetric characteristics rather than only gestational age. The utility of these fibrin-linked markers as a tool for exclusion of venous thromboembolism in pregnancy might be improved by adjusting for patient-specific characteristics.
authors.affiliation: Harris Birthright Research Center for Fetal Medicine, King's College Hospital Foundation Trust, London, United Kingdom.
authors.forename: Karin B
authors.initials: KB
authors.lastname: Grossman
authors.affiliation: King's Thrombosis Center, Department of Hematological Medicine, King's College Hospital Foundation Trust, London, United Kingdom. Electronic address: roopen.arya@nhs.net.
authors.forename: Roopen
authors.initials: R
authors.lastname: Arya
authors.affiliation: Harris Birthright Research Center for Fetal Medicine, King's College Hospital Foundation Trust, London, United Kingdom.
authors.forename: Alberto B
authors.initials: AB
authors.lastname: Peixoto
authors.affiliation: Harris Birthright Research Center for Fetal Medicine, King's College Hospital Foundation Trust, London, United Kingdom.
authors.forename: Ranjit
authors.initials: R
authors.lastname: Akolekar
authors.affiliation: Department of Obstetrics and Gynecology, Medical School of Hanover, Hannover, Germany.
authors.forename: Ismini
authors.initials: I
authors.lastname: Staboulidou
authors.affiliation: Harris Birthright Research Center for Fetal Medicine, King's College Hospital Foundation Trust, London, United Kingdom.
authors.forename: Kypros H
authors.initials: KH
authors.lastname: Nicolaides
mesh_terms: D000328:Adult; D044466:Asian People; D044383:Black People; D001835:Body Weight; D002908:Chronic Disease; D019970:Cocaine-Related Disorders / Q000097:blood; D005260:Female; D005338:Fibrin Fibrinogen Degradation Products / Q000378:metabolism*; D005865:Gestational Age; D006801:Humans; D006973:Hypertension / Q000097:blood; D011247:Pregnancy; D011249:Pregnancy Complications, Cardiovascular / Q000097:blood* / Q000175:diagnosis*; D011446:Prospective Studies; D012016:Reference Values; D012805:Sickle Cell Trait / Q000097:blood; D054556:Venous Thromboembolism / Q000097:blood* / Q000175:diagnosis*; D044465:White People
chemical_list: D005338:Fibrin Fibrinogen Degradation Products; C036309:fibrin fragment D; C011468:fibrinmonomer
keywords: D-dimer; fibrin monomer complex; pregnancy; screening; venous thromboembolism