ORIGINAL ARTICLE| Volume 20, ISSUE 3, P213-218, July 2011

Use of thromboelastography to guide thromboprophylaxis after caesarean section



      Thromboprophylaxis is commonly required following caesarean section. However the effect of thromboprophylactic dosages of subcutaneous heparin on coagulation is unknown because conventional laboratory tests are largely unaffected. The aim of this study was to determine if thromboelastography could detect and quantify the effect of unfractionated heparin on coagulation profile when given at the time of surgery.


      Nineteen women undergoing elective caesarean section were recruited. Blood samples collected before and after administration of subcutaneous unfractionated heparin 7500 IU underwent thromboelastography using both plain and heparinase cuvettes. Anti-factor Xa levels were also measured.


      There was a significant difference in R times between plain and heparinase samples (−10.6%, P = 0.0072) indicating that thromboelastography could detect an effect of unfractionated heparin. Compared to baseline there were significant decreases of R times in plain (−20.4%, P = 0.033) and heparinase (−28.8%, P = 0.0001) samples despite the administration of unfractionated heparin. Anti-factor Xa levels were virtually undetectable (mean 0.01 U/mL).


      Thromboelastography was able to detect and quantify the effect of unfractionated heparin on blood coagulability, an effect not detected by conventional laboratory tests. Thromboelastography demonstrated a pro-coagulant effect of surgery that was only partially mitigated by the use of unfractionated heparin. In this study, at a dose of 7500 IU subcutaneous unfractionated heparin appears to have little anticoagulant effect.


      To read this article in full you will need to make a payment

      Purchase one-time access:

      Academic & Personal: 24 hour online accessCorporate R&D Professionals: 24 hour online access
      One-time access price info
      • For academic or personal research use, select 'Academic and Personal'
      • For corporate R&D use, select 'Corporate R&D Professionals'


      Subscribe to International Journal of Obstetric Anesthesia
      Already a print subscriber? Claim online access
      Already an online subscriber? Sign in
      Institutional Access: Sign in to ScienceDirect


      1. Lewis G, editor. The Confidential Enquiry into Maternal and Child Health (CEMACH): Saving Mother’s Lives. Reviewing maternal deaths to make motherhood safer. The Seventh Report of the Confidential Enquiries into Maternal Deaths in the United Kingdom 2003–2005. London, CEMACH, 2007.

        • Morris J.M.
        • Algert C.S.
        • Roberts C.L.
        Incidence and risk factors for pulmonary embolism in the postpartum period.
        J Thromb Haemost. 2010; 8: 998-1003
        • James A.H.
        • Jamison M.G.
        • Brancazio L.R.
        • et al.
        Venous thromboembolism during pregnancy and the postpartum period: incidence, risk factors, and mortality.
        Am J Obstet Gynecol. 2006; 194: 1311-1315
      2. Caesarean section. Clinical Guideline commissioned by National Institute for Clinical Excellence. RCOG Press, Bell and Bain Ltd, April 2004.

        • Nelson-Piercy C.
        • Letsky E.A.
        • de Swiet M.
        Low molecular weight heparin for obstetric prophylaxis: experience of sixty-one women at high risk.
        Am J Obstet Gynecol. 1997; 176: 1062-1068
        • Carroll R.
        • Craft R.M.
        • Whitaker G.L.
        Thromboelastographic monitoring of resistance to enoxaparin anticoagulation in thrombophilic pregnancy.
        Thromb Res. 2007; 120: 367-370
        • Nelson-Piercy C.
        Obstetric thromboprophylaxis.
        Br J Hosp Med. 1996; 55: 404-408
        • Brancazio L.R.
        • Roperti K.A.
        • Stierer R.
        • Laifer S.A.
        Pharmacokinetics and pharmacodynamics of subcutaneous heparin during the early third trimester of pregnancy.
        Am J Obstet Gynecol. 1995; 173: 1240-1245
        • Barbour L.A.
        • Smith J.M.
        • Marlar R.A.
        Heparin levels to guide thromboembolism prophylaxis during pregnancy.
        Am J Obstet Gynecol. 1995; 173: 1869-1873
      3. Reducing the risk of thrombosis and pregnancy during the puerperium. RCOG Green Top Guideline No. 37 2009. [accessed March 2011].

        • Mallett S.V.
        • Cox D.J.A.
        Br J Anaesth. 1992; 69: 307-313
        • Pivalizza E.G.
        Heparinase and thromboelastography in liver transplantation for a patient with von Willebrand’s disease.
        Anesthesiology. 1996; 84: 1236-1239
        • Harding S.A.
        • Mallett S.V.
        • Peachy T.D.
        • Cox D.J.
        Use of heparinase modified thromboelastography in liver transplantation.
        Br J Anaesth. 1997; 78: 175-179
      4. National Clinical Guideline Centre – Acute and Chronic conditions. Venous thromboembolism: Reducing the risk of venous thromboembolism (Deep vein thrombosis and Pulmonary embolism) in patients admitted to hospital. London NCGC-ACC at the Royal College of Surgeons of England; in press. Clinical guideline [accessed March 2011].

        • Matzelle S.J.
        • Gibbs N.M.
        • Weightman W.
        • et al.
        Systemic anticoagulant effect of low dose subcutaneous unfractionated heparin as determined using thromboelastography.
        Anaesth Intensive Care. 2007; 35: 498-504
        • Dahlman T.C.
        • Hellgren M.S.
        • Blomback M.
        Thrombosis prophylaxis in pregnancy with the use of subcutaneous heparin adjusted by monitoring heparin concentration in plasma.
        Am J Obstet Gynecol. 1989; 161: 420-514
        • Klein S.M.
        • Slaughter T.F.
        • Parker T.
        • et al.
        Thromboelastography as a perioperative measure of anticoagulation resulting from low molecular weight heparin: a comparison with anti-Xa concentrations.
        Anesth Analg. 2000; 91: 1091-1095
        • Saha P.
        • Stott D.
        • Atalla R.
        Haemostatic changes in the puerperium ‘6 weeks postpartum’ (HIP study) – implication for maternal thromboembolism.
        BJOG. 2009; 116: 1602-1612
        • Szecsi P.B.
        • Jorgensen M.
        • Klajnbard A.
        • et al.
        Thromb Haemost. 2010; 103: 718-727
        • Boer K.
        • Hollander I.A.
        • Meijers J.C.
        • et al.
        Tissue factor-dependent coagulation is enhanced following delivery irrespective of the mode of delivery.
        J Thromb Haemost. 2007; 5: 2415-2420
        • Butwick A.J.
        • Carvalho B.
        Neuraxial anaesthesia in obstetric patients receiving anticoagulant and antithrombotic drugs.
        Int J Obstet Anesth. 2010; 19: 193-201
        • Chunilal S.D.
        • Yound E.
        • Johnston M.A.
        • et al.
        The APTT response of pregnant plasma to unfractionated heparin.
        J Thromb Haemost. 2002; 87: 92-97
        • Stirrup C.A.
        • Lucas D.N.
        • Cox M.L.
        • et al.
        Maternal anti-factor Xa activity following subcutaneous unfractionated heparin after caesarean section.
        Anaesthesia. 2001; 56: 855-858
        • Steer P.L.
        • Krantz H.B.
        Thromboelastography and sonoclot analysis in the healthy parturient.
        J Clin Anesth. 1993; 5: 419-424
        • Wong C.A.
        • Liu S.
        • Glasenberg R.
        Comparison of thromboelastography with common coagulation tests in pre eclampsia and healthy parturients.
        Reg Anesth. 1995; 20: 521-527
        • Sharma S.K.
        • Philip J.
        • Wiley J.
        Thromboelastographic changes in healthy parturients and post partum women.
        Anesth Analg. 1997; 85: 94-98
        • Sharma Shiv K.
        • Philip J.
        The effect of anesthetics on blood coagulability in parturients as measured by thromboelastography.
        Anesth Analg. 1997; 85: 82-86
        • Butwick A.
        • Carvalho B.
        The effect of colloid and crystalloid preloading on thromboelastography prior to cesarean delivery.
        Can J Anesth. 2007; 54: 190-195
        • Bonnar J.
        • Norris L.A.
        • Greene R.
        Low molecular weight heparin for thromboprophylaxis during caesarean section.
        Thromb Res. 1999; 96: 317-322
        • Gibson J.L.
        • Ekevall K.
        • Walker I.
        • Greer I.A.
        Puerperal thromboprophylaxis: a comparison of the anti-Xa activity of enoxaparin and unfractionated heparin.
        BJOG. 1998; 105: 795-797
        • Norris L.
        • Bonnar J.
        • Smith M.P.
        • Steer P.J.
        Savidge G, Low molecular weight heparin (tinzaparin) therapy for moderate risk thromboprophylaxis during pregnancy.
        J Thromb Haemost. 2004; 92: 791-796