Thrombosis during pregnancy and the postpartum period.

OBJECTIVE: To describe the circumstances surrounding deep vein thrombosis among pregnant or postpartum patients enrolled in a large multicenter registry.

STUDY DESIGN: Consecutive patients with ultrasound-confirmed deep vein thrombosis were enrolled at 183 institutions during a 6-month period from October 2001 to March 2002. Fifty-three who were either pregnant or within 6 weeks postpartum were analyzed.

RESULTS: Thirty-four were pregnant and 19 were postpartum. Among those pregnant, 44% experienced deep vein thrombosis in the first trimester, 24% in the second, and 26% in the third. Deep vein thrombosis occurred in the left lower extremity in 76% of the pregnant and 47% of the postpartum women. Four pregnant and 2 postpartum women had pelvic vein thrombosis. Among those postpartum, 74% had undergone surgery within 3 months.

CONCLUSION: During pregnancy, the risk of deep vein thrombosis begins in the first trimester. Thus, we believe that when prophylaxis is indicated, it should be initiated early in gestation.