Clinical Edge

Summaries of Must-Read Clinical Literature, Guidelines, and FDA Actions

Risk of Thromboembolism in Pregnancy

Obstet Gynecol; ePub 2018 Jul; James, et al

The prevalence and severity of thromboembolism during pregnancy warrant special consideration of management and therapy, including the treatment of acute thrombotic events and prophylaxis for those at increased risk of thrombotic events. This according a revised practice bulletin from the American College of Obstetricians and Gynecologists (ACOG) that reflects updated guidance regarding screening for thromboembolism risk and management of anticoagulation around the time of delivery. Among the ACOG recommendations and conclusions:

  • When signs or symptoms suggest new onset deep vein thrombosis (DVT), the recommended initial diagnostic test is compression ultrasonography of the proximal veins. (Level A)
  • In general, the preferred anticoagulants in pregnancy are heparin compounds. (Level B)
  • Because of its greater reliability and ease of administration, low-molecular-weight heparin is recommended rather than unfractionated heparin for prevention and treatment of VTE within and outside of pregnancy. (Level B)
  • A reasonable approach to minimize postpartum bleeding complications is resumption of anticoagulation therapy no sooner than 4–6 hours after vaginal delivery or 6–12 hours after cesarean delivery. (Level B)
  • Because warfarin, low-molecular-weight heparin, and unfractionated heparin do not accumulate in breast milk and do not induce an anticoagulant effect in the infant, these anticoagulants are compatible with breastfeeding. (Level B)
  • Women with a history of thrombosis who have not had a complete evaluation of possible underlying etiologies should be tested for antiphospholipid antibodies and for inherited thrombophilias. (Level C)
  • Adjusted-dose (therapeutic) anticoagulation is recommended for women with acute thromboembolism during the current pregnancy or those at high risk of thrombosis, such as women with a history of recurrent thrombosis or mechanical heart valves. (Level C)


Thromboembolism in pregnancy. ACOG Practice Bulletin No. 196. American College of Obstetricians and Gynecologists. Obstet Gynecol. 2018;132:e1‒17.