Prophylaxis and treatment of thromboembolic diseases during pregnancy with dalteparin

Objectives: To determine if a prophylactic dose of dalteparin, 5000 IU daily, and if the adjusted-weight dalteparin therapeutic dose of 100 IU/kg twice daily are appropriate in pregnancy. Method: Anti-Xa activity levels were used to assess prophylactic (33 women) and therapeutic (15 women) dalteparin dosage throughout pregnancy. Analysis of variance was used and P-values less than 0.05 were considered statistically significant. Results: In the prophylactic group, anti-Xa activity levels did not vary significantly throughout pregnancy (P=0.15). The initial dalteparin dose was modified on the first anti-Xa activity measurement in eight women, whose weight was statistically different from those remaining on the initial dose (P<0.001). The adjusted-weight therapeutic dalteparin dose induced adequate anti-Xa activity levels. Conclusions: Dalteparin, 5000 IU daily, is suitable for most pregnant women and does not need to be modified in the third trimester. A therapeutic dalteparin dose adjusted according to pregnancy weight is appropriate.