Subcutaneous Heparin Therapy during Pregnancy: a Need for Concern at the Time of Delivery

Summary

Subcutaneous heparin is the treatment of choice for women requiring anticoagulant therapy during pregnancy. However, heparin therapy presents a management problem at delivery because of its potential to cause a persistent anticoagulant effect and thus increase the risk of bleeding. In order to avoid therapeutic complications it has been our practice to have women eithei discontinue their heparin injections with the onset of labour or to terminate heparin injections 12 h prior to elective induction. To determine the safety of our anticoagulant protocol at delivery we reviewed consecutive patients treated with subcutaneous heparin therapy during pregnarcl, at our centre. Over a 23 month period we found that six of 11 women receiving subcutaneous heparin during pregnancy delivered while their aPTT was prolonged. In addition, three women received intravenous protamine sulphate prior to delivery and in one patient major bleeding occurred during an emergency cesarean section. Those women who had elevated aPTTs at the time of delivery all gave birth within 28 h of their last injection of heparin. In order to avoid a prolonged aPTT at delivery, we have now adopted a more conservative approach to the management of subcutaneous heparin use at term. Subcutaneous heparin is discontinued 24 h prior to commencing an elective induction of labour.

• REFERENCES

• 1 Ginsberg JS, Hirsh J, Turner DC, Levine MN, Burrows R. Risks to the fetus of anticoagulant therapy during pregnancy. Thromb Haemostas 1989; 61: 197-203
• 2 Ginsberg JS, Kowalchuk G, Hirsh J, Brill-Edwards P, Burrows R. Heparin therapy during pregnancy: risks to the fetus and mother. Arch Intern Med 1989; 149: 2233-2236
• 3 Hathaway WE, Bonnar J. Perinatal Coagulation. Grune and Stratton, New York 1978: 181-186
• 4 Chiu HM, Hirsh J, Yung WL, Regoeczi E, Gent M. Relationship between the anticoagulant and antithrombotic effects of heparin in experimental venous thrombosis. Blood 1977; 49: 171-184
• 5 Hyers TM, Hull RD, Weg JG. Antithrombotic therapy for venous thromboembolic disease. Chest 1989; 95 S: 37 S-51 S
• 6 Hirsh J, O’Sullivan EF, Gallus AS, Martin M. Evaluation of subcutaneous calcium heparin therapy in the treatment of thromboembolic disease. Med J Aust 1970; 1: 15-17
• 7 Boneu B, Caranobe C, Gabaig AM. et al Evidence for a saturable mechanism of disappearance of standard heparin in rabbits. Thromb Res 1987; 46: 835-844