BMJ 2017;357:j2344 doi: 10.1136/bmj.j2344 (Published 2017 May 31)
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Practice
PRACTICE CLINICAL UPDATE
Diagnosis and management of deep vein thrombosis in pregnancy 1 2
Faizan Khan MSc epidemiology student , Christian Vaillancourt associate professor of emergency 1 2 3 medicine, emergency physician , Ghada Bourjeily associate professor of medicine, pulmonary 4 and critical care, obstetric medicine physician 1
Faculty of Medicine, University of Ottawa, Ottawa, ON, Canada K1H 8L6; 2Clinical Epidemiology Program, Ottawa Hospital Research Institute, Ottawa, ON, Canada; 3Department of Emergency Medicine, The Ottawa Hospital, Ottawa, ON, Canada; 4Warren Alpert Medical School of Brown University, The Miriam Hospital, Providence, RI, USA
Venous thromboembolism includes deep vein thrombosis (DVT) and pulmonary embolism. In DVT a blood clot forms in the lower extremities that may break off and travel to the lungs causing a pulmonary embolism. DVT is more common than pulmonary embolism during pregnancy1 and will constitute the focus of this clinical update. However, the prevalence, risk factors, and therapeutic options for DVT and venous thromboembolism in pregnancy are closely linked, and thus information regarding venous thromboembolism in pregnancy has also been covered where appropriate or when data regarding DVT are unavailable. Among pregnant women, pulmonary embolism is the most serious complication of DVT and remains one of the leading causes of maternal death in the developed world.2 Pregnancy related DVT is associated with a higher risk of embolic complications and of the post-thrombotic syndrome (chronic leg pain, intractable oedema, leg ulcers) than DVT in non-pregnant women.1 3 This article provides an update on the diagnosis and management of pregnant women with DVT.
How common is DVT in pregnancy? The risk of venous thromboembolism in pregnancy is about four times the risk among non-pregnant women of childbearing age4; it is highest in the third trimester5 6 and increases further in the first six weeks post partum.1-7 The incidence of DVT among pregnant women is around 1.1 per 1000 deliveries.5 The risk of pregnancy related DVT is approximately three times higher than pregnancy related pulmonary embolism.5
What is the pathophysiology of DVT in pregnancy? Pregnancy is associated with hypercoagulability. There is an increase in procoagulant and a decrease in anticoagulant and fibrinolytic activity in preparation for delivery as well as venous stasis.8 Vascular damage in the pelvis also occurs around labour and delivery. These changes are consistent with Virchow’s triad (hypercoagulability, venous stasis, and vascular damage) (fig 1⇓). In pregnancy the uterus can compress the left iliac vein and may explain why DVT is significantly more common on the left side in pregnancy (>80% of cases). DVT is more commonly diagnosed in the pelvic venous system in pregnancy (>60% of cases) compared with the non-pregnant population.9
How is DVT diagnosed in pregnancy? Clinical presentation Pregnant women with DVT most commonly present with discomfort (80-95%) and oedema (80-88%) in a lower extremity.10 Symptoms are more likely to be left sided. Isolated lower abdominal or pelvic pain may rarely be the presenting symptoms of a pelvic DVT.11 Clinicians must maintain a high level of suspicion for DVT in pregnant women and arrange diagnostic tests promptly to minimise the risk of embolic complications and of post-thrombotic syndrome (chronic leg pain, intractable oedema, and leg ulcers).1 12 In a case-control study, post-thrombotic syndrome was reported in 42% of women with pregnancy related DVT.3
Correspondence to: F Khan fkhan039@uottawa.ca For personal use only: See rights and reprints http://www.bmj.com/permissions
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