Effect of Heparin on Antithrombin III Activity During Delivery and Early Puerperium

Abstract

It is known that antithrombin III (AT III) is the main inhibitor of blood coagulation. It inactivates thrombin and activated × factor. Heparin increases the AT III activity in vitro as well as in vivo. The authors have studied the AT III activity in sera of 30 pregnant women, at term, before labour started (2–24 hrs) and 30 as well as 60 min after the birth of placenta and daily for five days after delivery. The AT III activity was determined using the modified method of Gerendas. Out of the 30 women 15 were given 5000 IU heparin subcutaneously 1½—2 hours before delivery. In the 15 women with no heparin treatment AT III activity of serum significantly decreased after birth of placenta compared with the predelivery value and became normal on the fifth postpartum day. Heparin given subcutaneously prevented development of this decrease.