Venous thromboembolism in pregnancy and the puerperium

A 33-year-old woman at 34 weeks gestation, BMI 38, presents to the maternity assessment unit with a one-day history of left calf swelling and pleuritic chest pain. She had an emergency caesarean in her first pregnancy and a maternal aunt with a pulmonary embolism. Her oxygen saturation is 96 per cent on room air. This is VTE until proven otherwise, and the next two hours will decide whether the diagnosis is made safely. The decisions — diagnostic pathway, anticoagulation dose, the planned delivery and the postpartum duration — are the decisions this topic rehearses.[1][3]

Overview and definition

Venous thromboembolism in pregnancy encompasses deep vein thrombosis (DVT) and pulmonary embolism (PE) occurring during pregnancy or within six weeks of delivery. It is one of the leading direct causes of maternal mortality in high-income settings, and it is largely preventable with appropriate risk assessment and prophylaxis.[1][3]

Three principles frame the topic:[1]

• Pregnancy is a hypercoagulable state. VTE risk is four to five times that of non-pregnant women of the same age, and the postpartum period carries the highest risk.[3]
• Diagnosis is harder in pregnancy. Symptoms overlap with physiological pregnancy complaints, d-dimer is raised throughout pregnancy, and the choice of imaging must weigh maternal and fetal radiation dose.[4][9]
• Treatment is heparin, not warfarin. Low-molecular-weight heparin is the agent of choice for both treatment and prophylaxis; warfarin is teratogenic in weeks 6 to 12 and causes fetal intracranial haemorrhage in the third trimester.[1][2]

Two numbers anchor the topic. The prevalence of pregnancy-related VTE is roughly 1 to 2 per 1000 pregnancies, and the postpartum period accounts for a disproportionate share of fatal events.[3][16]

References16Show ledgerHide ledger

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2. [2]Bates SM, Greer IA, Middeldorp S, et al. VTE, thrombophilia, antithrombotic therapy, and pregnancy: Antithrombotic Therapy and Prevention of Thrombosis, 9th ed: American College of Chest Physicians Evidence-Based Clinical Practice Guidelines Chest, 2012.PMID 22315276
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