Thromboembolism is a major cause of maternal mortality. Pregnancy is a risk factor for venous thromboembolism (VTE) and seems to increase the risk tenfold in comparison with non-pregnant women (RCOG Guidelines, 2004). The risk is even higher if delivery is by caesarean section, especially emergency caesarean section1.
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Although it is associated with high degrees of morbidity and mortality, VTE during pregnancy and the immediate postnatal period is rare. The Cochrane review data identified the best estimate of incidence as 0.13%2 , however estimates varying from 0.06%3to 0.11%4 have been published.
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Some groups of women have a higher risk of developing VTE. Although a number of risk factors have been reliably identified, the size of the increases in risk attributable to these factors is generally poorly quantified.
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Since the introduction of the RCOG guidelines for thromboprophylaxis in 1995, a fall in deaths from VTE after Caesarean section has been observed in the UK (Why Mothers Die 1997-1999: The fifth report of the confidential enquiries into maternal deaths in the United Kingdom, RCOG Press, 2001).
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The RCOG recommendations were reached by consensus without evidence from randomised controlled trials. The Cochrane collaboration has identified a paucity of adequately conducted trials upon which to base recommendations.
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Definition of terms
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Pharmacological methods: Low molecular weight heparin, warfarin, aspirin
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Non-pharmacological methods: Stockings, pneumatic compression, early mobilisation and surveillance
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Management
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Risk assessment
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Prior to Caesarean section, assess all women for VTE risk factors (see Table 1). Management is according to level of risk (i.e. low, moderate or high).
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Table 1: RCOG Risk assessment profile for thrombo-embolism in caesarean section (5)
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| - Elective caesarean section with umcomplicated pregnancy and no other risk factors
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| Early mobilistaion and hydration
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| - Age >35
- Obesity BMI>30
- Para 4 or more
- Gross varicose veins
- Current infection
- Pre-eclampsia
- Immobility prior to surgery (>4days)
- Major systemic illness, eg. heart/lung disease, inflammatory bowel disease: nephritic syndrome
- Nephrotic syndrome, sickle cell disease
- Emergency caesarean in labour
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| Low molecular weight heparin prophylaxis
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| - Patients with 3 or more risk factors
- Extended surgery, e.g. caesarean hysterectomy
- Personal or family history of deep vein thrombosis; pulmonary embolism or thrombophilia; paralysis of lower limbs
- Patients with antiphospholipid antibody (cardiolipin antibody or lupus anticoagulant)
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| Low molecular weight heparin prophylaxis +/- leg stockings
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Contraindications
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- Primary postpartum haemorrhage (PPH) >1000mls
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- Individual risks of bleeding as assessed by treating physician or surgeon
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- Severe coagulation disorders
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- Haemorrhage prone ulcerative conditions
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- History of immunologically mediated heparin induced thrombocytopenia
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Precautions
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- Severe hepatic & / or renal insufficiency
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- Familial antithrombin III deficiency
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- Q-wave myocardial infarction
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- Uncontrolled hypertension
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- Hypertensive diabetic retinopathy
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Prophylaxis
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Pharmacological
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Where level of risk indicates thromboprophylaxis, the initial dose is administered postoperatively (although the current RCOG guidelines suggest prophylaxis prior to surgery) due to the possibility of spinal haematoma.
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The following regime for thromboprophylaxis post caesarean is based on the only RCT to compare thromboprophylaxis with placebo6.
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Thromboprophylaxis regime for post caesarean
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 | - Dalteparin (Fragmin) 5000 IU S/C to upper thigh, every 24 hours.
- First dose to be administered no sooner than 4 hours post-operatively and no later than 24 hours post-operatively.
- Treatment is to be continued for a minimum of 4 days
- Treatment is to be reviewed by medical officer at 5 days to assess continued need for prophylactic low molecular weight heparin.
- A post-operative haemoglobin and platelet count is suggested but not required.
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Non-pharmacological
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Stockings
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There have been no studies to evaluate the use of non-pharmacological methods (including stockings). Therefore low molecular weight heparin is the preferred method of thromboprophylaxis.
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Notes
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Both pharmacological methods and non-pharmacological methods have been used. No studies have evaluated the use of non-pharmacological methods.
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Pharmacological methods are known to have a number of side effects. When used after caesarean section, low molecular weight heparin may increase the frequency of bleeding and wound complications.
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There have been studies assessing the use of low molecular weight heparin compared with standard heparin on the risk of thromboembolic disease following major abdominal surgery and the result seems to be comparable in terms of therapeutic efficacy5, 7. However the studies have been too small to comment on postoperative complications.
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One randomised controlled trial specifically assessed complications following use of both types of heparin8. Although the primary outcome measure of total bleeding events failed to reach statistical significance (p=0.058), low molecular weight heparins had advantages in subgroup analysis including reductions in re-operation and minor bleeding episodes which has been confirmed by another publication9.
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Aspirin has been used for thromboprophylaxis in orthopaedic surgery(10) (PEP Trial 2000) but awaits confirmation of its usefulness post caesarean section.
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References
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1. Bates S M, Greer I A, Hirsh J, Ginsberg J S Use of antithrombotic agents during pregnancy: the Seventh ACCP Conference on Antithrombotic and Thrombolytic Therapy. [Review] [119 refs]. Chest. 126(3 Suppl):627S-644S, 2004 Sep.
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2. Gates S, Brocklehurst P, Davis L J Prophylaxis for venous thromboembolic disease in pregnancy and the early postnatal period. [Review] [40 refs]. Cochrane Database of Systematic Reviews. (2):CD001689, 2002.
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3. Gherman R B, Goodwin T M, Leung B, Byrne J D, Hethumumi R, Montoro M Incidence, clinical characteristics, and timing of objectively diagnosed venous thromboembolism during pregnancy. Obstetrics & Gynecology. 94(5 Pt 1):730-4, 1999 Nov.
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4. Macklon N S, Greer I A Venous thromboembolic disease in obstetrics and gynaecology: the Scottish experience. Scottish Medical Journal. 41(3):83-6, 1996 Jun.
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5. Koller M, Schoch U, Buchmann P, Largiader F, von Felten A, Frick P G Low molecular weight heparin (KABI 2165) as thromboprophylaxis in elective visceral surgery. A randomized, double-blind study versus unfractionated heparin. Thrombosis & Haemostasis. 56(3):243-6, 1986 Dec 15.
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6. Burrows R F, Gan E T, Gallus A S, Wallace E M, Burrows E A A randomised double-blind placebo controlled trial of low molecular weight heparin as prophylaxis in preventing venous thrombolic events after caesarean section: a pilot study. BJOG: an International Journal of Obstetrics & Gynaecology. 108(8):835-9, 2001 Aug.
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7. Anonymous Comparison of a low molecular weight heparin and unfractionated heparin for the prevention of deep vein thrombosis in patients undergoing abdominal surgery. The European Fraxiparin Study (EFS) Group. British Journal of Surgery. 75(11):1058-63, 1988 Nov.
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8. Kakkar V V, Cohen A T, Edmonson R A, et al Low molecular weight versus standard heparin for prevention of venous thromboembolism after major abdominal surgery. The Thromboprophylaxis Collaborative Group.[see comment]. Lancet. 341(8840):259-65, 1993 Jan 30.
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9. Boneu B An international multicentre study: Clivarin in the prevention of venous thromboembolism in patients undergoing general surgery. Report of the International Clivarin Assessment Group. Blood Coagulation & Fibrinolysis. 4 Suppl 1:S21-2, 1993 Dec.
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10. Anonymous Prevention of pulmonary embolism and deep vein thrombosis with low dose aspirin: Pulmonary Embolism Prevention (PEP) trial.[see comment]. Lancet. 355(9212):1295-302, 2000 Apr 15.
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Links
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RCOG GreenTop Guideline No: 37 (January 2004) - Thromboprophylaxis during pregnancy labour and after vaginal delivery.
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The Women's Policy & Procedure Manual - Medication Policy (intranet access only)
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Royal Women's Hospital Clinical Practice Guidelines are intended to provide guidance to health care professionals, based on a thorough evaluation of research evidence, on the practical assessment and management of specific clinical issues or situations. Clinical Practice Guidelines (CPGs) allow some flexibility on the part of the health care professional based on the needs of the specific patient for whom they are caring.
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