ABSTRACT
OBJECTIVES: A group of 50 pregnant patients were studied with regard to the time of onset of hypercoagulation, its character and mechanisms of initiation in the development of preeclampsia. METHODS: The blood coagulation characteristics, antithrombin (AT)-III and endogenous heparin levels were studied. All of the patients were designated at risk of developing preeclampsia at the time of registration at the antenatal clinic. RESULTS: Retrospective evaluation shows that endogenous heparin levels and AT-III activity decreased by nearly 50% within 15 days of the development of preeclampsia and were particularly low 1-7 days before the onset of clinical signs of preeclampsia. CONCLUSIONS: These findings indicate that abnormalities in AT activity are a marker of hypercoagulation and begin more than 2 weeks before the development of clinical signs of preeclampsia.