MATERNAL AND EARLY CHILD HEALTH

Health Evidence Bulletins - Wales

Date of Completion: 23.6.97

The contents of this bulletin are likely to be valid for approximately one year, by which time significantly new research evidence may become available


8. Thromboembolism in pregnancy

(Users are advised to consult the supporting evidence for a consideration of all the implications of a recommendation)

The Statements The Evidence
8a. Pregnant women and, in particular, those with a history of thromboembolic disease are at appreciable risk during pregnancy. The reported incidence of deep vein thrombosis (DVT) and non-fatal pulmonary embolism varies considerably because of the peculiar diagnostic difficulties in pregnancy. Real time ultrasound scanning combined with Doppler studies, being noninvasive, are the first line diagnostic techniques for DVT in pregnancy (i).
(Health gain notation - 2 "likely to be beneficial")
i. Report of the RCOG Working Party. Prophylaxis and management against thromboembolism in gynaecology and obstetrics. London: Royal College of Obstetricians and Gynaecologists, 1995. p.15

(Type V evidence - expert opinion)

8b. In the absence of randomised controlled trials of sufficient size in the obstetric literature, current recommendations for management are derived from nonpregnant population trials and observational studies in pregnancy (i,ii).

Well designed trials are needed in this area.

i. Barbour LA, Pickard J. Controversies in thromboembolic disease during pregnancy: a critical review Obstetrics and Gynecology 1995; 86:621-33
(Type V evidence - expert opinion);
ii. Report of the RCOG Working Party. Prophylaxis and management against thromboembolism in gynaecology and obstetrics. London: Royal College of Obstetricians and Gynaecologists, 1995
(Type V evidence - expert opinion)
8c. The majority of deaths from pulmonary embolism following Caesarean Section occur after the first week of the puerperium, after discharge from hospital. All those involved with the care of women in the puerperium must be alert to this possibility (i).
(Health gain notation - 2 "likely to be beneficial")
i. Department of Health and Others. Report on Confidential Enquiries into Maternal Deaths in the United Kingdom. 1991-1993. London: HMSO, 1996. p.52
(Type V evidence - expert opinion)

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8d. In the UK, Heparin and Warfarin are the two anticoagulants relevant to clinical practice in pregnancy. They each require special consideration regarding safety in pregnancy(i)i.
(Health gain notation - 2 "likely to be beneficial")
i. Clagett CJ, Reisch CJ. Prevention of venous thromboembolism in general surgical patients. Results of a metanalysis. Annals of Surgery. 1988; 208(2): 227-40
(Type I evidence - meta analysis)
8e. Detailed recommendations for prophylaxis and management have been published by the Royal College of Obstetricians and Gynaecologists, based on best available evidence and assessment of risk factors including evidence from general surgery. These are summarised below i.
(Health gain notation - 1 "beneficial")
Prophylaxis against thromboembolic disease following Caesarean section:
  • a risk assessment should be performed
  • in uncomplicated pregnancy only early mobilisation and attention to hydration are required.
  • patients at moderate risk should receive subcutaneous heparin or mechanical methods.
  • patients at high risk should receive heparin prophylaxis and, in addition, leg stockings would be beneficial.
  • prophylaxis should be continued for 5 days.
  • the use of subcutaneous heparin in patients with an epidural or spinal block remains contentious. Current evidence from general surgery does not point to an increased risk of spinal haematoma.

Prophylaxis against thromboembolism in pregnancy:

  • patients with a past history of thromboembolism in pregnancy/puerperium (and no other risk factor) should receive thromboprophylaxis for 6 weeks postpartum.
  • patients at high risk (multiple previous thromboembolism) may require anticoagulation in pregnancy.

Diagnosis and management:

  • the importance of accurate diagnosis is stressed. Inappropriate full anticoagulation carries risk to mother and fetus and has long term implications for contraceptive methods and management of subsequent pregnancy.
  • the duration of anticoagulation in patients with proven deep vein thrombosis should be for local policy agreements but is likely to be for a minimum of three months.
i. Report of the RCOG Working Party on prophylaxis (and management) against Thromboembolism in Gynaecology and Obstetrics. London: Royal College of Obstetricians and Gynaecologists, 1995

(Type V evidence - expert opinion)

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Health Evidence Bulletins: Wales, Duthie Library, UWCM, Cardiff CF14 4XN. e-mail: weightmanal@cardiff.ac.uk