THROMBOEMBOLIC PROPHYLAXIS WITH LOW-MOLECULAR-WEIGHT HEPARIN DURING PREGNANCY

Objective: The objective of this study was to show that low molecular weight heparin (LMWH) can be used in preventing veno-pulmonary thrombo embolic diseases in pregnancy. Methods: Twenty-four women carrying 27 pregnancies with known risk of veno-pulmonary thromboembolic diseases in pregnancy were prophylactically treated with LMWH (dalteparin) duri ng part of their pregnancy. Our therapeutic target was a plasma concen tration of 0.20-0.50 anti-Xa U/ml measured 2-6 h after subcutaneous ad ministration of LMWH into the abdominal wall. To obtain this anti-Xa a ctivity the patients were given total doses of 2500-10 000 anti-Xa U d aily. Monitoring of anti-Xa activity in patients receiving less than o r equal to 5000 U/day was not necessary. Results: Twelve out of the 24 women received LMWH at the time of delivery. Our biochemical assay co uld not show the presence of anti-Xa activity in the blood samples fro m the babies although it was possible to show anti-Xa activity in thei r mothers. In three out of 24 women, blood samples showed activation o f coagulation. These patients were changed to the vitamin K antagonist phenindione. Conclusion. None of the treated women showed any clinica l or paraclinical signs of thromboembolic diseases during pregnancy or 6 weeks postpartum. All the babies were born healthy. None of the wom en had any side effects due to the treatment.