Obstetric VTE risk assessment

What it is

The assessment is a documented score. All women should undergo a documented assessment of risk factors for venous thromboembolism in early pregnancy or pre-pregnancy; it is repeated if the woman is admitted to hospital for any reason or develops other intercurrent problems, and repeated again intrapartum or immediately postpartum. Another source has it completed at booking and on any subsequent hospital admission. A woman with previous VTE should be offered prepregnancy counselling and a prospective management plan for thromboprophylaxis in pregnancy. In pregnancy the drug used for anticoagulation is chosen with the fetus in mind. Enoxaparin is the most appropriate pharmacologic therapy for anticoagulation in patients who are pregnant. Aspirin is not used as treatment for deep vein thrombosis. Apixaban, warfarin and heparin either have not been studied for use in pregnancy or there is data indicating potential fetal harm, and warfarin is teratogenic and therefore contraindicated during pregnancy. Systemic anticoagulation is the cornerstone of treatment for thrombotic antiphospholipid syndrome, so what pregnancy changes is which drug, not whether to anticoagulate.

The pregnancy-induced changes in coagulation factors that favor clotting are a decrease in protein S and increases in fibrinogen, in factors VI, VII and X, and in von Willebrand factor. Venous stasis comes from compression of the pelvic veins by the gravid uterus and from endocrine-mediated venodilation, often aggravated by decreased mobility. The greatest risk of VTE is the first week postpartum, and especially after a c-section.