title: Changes in thromboelastography parameters in pregnancy, labor, and the immediate postpartum period.
abstract: OBJECTIVE
  To demonstrate changes in clot mechanics during pregnancy, and to determine the effect that delivery has on immediate postpartum thromboelastography parameters.
  
  
  METHODS
  In an observational cross-sectional/longitudinal study, thromboelastography was performed on whole blood aliquots obtained from women carrying singleton pregnancies attending a center in London, UK, between December 2013 and March 2014. Thromboelastography was repeated 6hours after delivery among patients recruited in the third trimester or labor. Bleeding questionnaires were completed and routine clinical/demographic data obtained.
  
  
  RESULTS
  Overall, 112 women were included. The thromboelastography parameters were significantly correlated with length of pregnancy. From the third trimester to the postpartum period, there was a significant decrease in time until fibrin formation (R value; 5.8 vs 5.0minutes, P=0.036) and in time to reach a certain clot strength (amplitude of 20mm; K value; 1.3 vs 1.1minutes, P=0.007). From established labor to after delivery, there was a significant increase in clot lysis at 60minutes after the maximum amplitude of clot formation (LY60; 1.8% vs 3.1%, P=0.001).
  
  
  CONCLUSIONS
  The present study describes a novel finding regarding changes in clot mechanics in late pregnancy/puerperium and supports the concept of using thromboelastography as part of the routine assessments at delivery.
authors.affiliation: Institute for Women's Health, University College London, Royal Free London NHS Foundation Trust, London, UK. Electronic address: normshreeve@gmail.com.
authors.forename: Norman E
authors.initials: NE
authors.lastname: Shreeve
authors.affiliation: Institute for Women's Health, University College London, Royal Free London NHS Foundation Trust, London, UK.
authors.forename: John A
authors.initials: JA
authors.lastname: Barry
authors.affiliation: Department of Obstetrics and Gynaecology, Royal Free London NHS Foundation Trust, London, UK.
authors.forename: Leah R
authors.initials: LR
authors.lastname: Deutsch
authors.affiliation: Katherine Dormandy Haemophilia Centre and Thrombosis Unit, Royal Free London NHS Foundation Trust, London, UK.
authors.forename: Keith
authors.initials: K
authors.lastname: Gomez
authors.affiliation: Department of Obstetrics and Gynaecology, Royal Free London NHS Foundation Trust, London, UK; Katherine Dormandy Haemophilia Centre and Thrombosis Unit, Royal Free London NHS Foundation Trust, London, UK.
authors.forename: Rezan A
authors.initials: RA
authors.lastname: Kadir
mesh_terms: D000328:Adult; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D007743:Labor, Obstetric / Q000502:physiology*; D008991:Monitoring, Physiologic; D018743:Perinatal Care; D006473:Postpartum Hemorrhage / Q000175:diagnosis*; D011237:Predictive Value of Tests; D011247:Pregnancy / Q000502:physiology*; D011250:Pregnancy Complications, Hematologic / Q000175:diagnosis*; D013916:Thrombelastography
keywords: Clotting; Labor; Pregnancy; Thromboelastography