Evidence-based On-call

Deep vein thrombosis

Clinical features

Ask about current or recent pregnancy ^b

(especially if known thrombophilia). ^c

Why?

Women during pregnancy and the puerperium are at increased risk for venous thromboembolism ^c , but it is rare (0.01% of pregnancies). ^b

Pregnancy especially with thrombophilia increases the risk of venous thromboembolism

Outcome	Risk Factor	PEER	OR (95% CI)	NNH (95% CI)
venous thromboembolism ^b	pregnant or puerperal not independent	0.021%	9.3 (3.6 to 24.1)	570 (200 to 1800)
venous thromboembolism ^c	thrombophilia and pregnant not independent	0.078%	9.0 (1.07 to 75)	160 (18 to 18000)