The aim of the study was to evaluate the prevalence of the GP Ia and GP IIIa polymorphisms in the group of women in labor, and to assess the risk of thrombosis associated with their occurrence.245 women in labor hospitalized between 1.01.2001 and 31.12.2003 r. were enrolled in the study. Patients were qualified for the study if detailed physical exam and past medical history excluded existence of known risk factors predisposing to thrombosis. Study group was composed of 72 women in childbirth, which at some point during current pregnancy or in early labor were diagnosed with thrombosis, and control group included 173 women in labor randomly picked from the group of patients with uncomplicated pregnancies. Polymorphic regions of platelets glycoprotein were detected using genotyping methods based on polymerase chain reactions (PCR).1.72% of patients were found to have thrombosis. The thrombosis was located in the venous system in 97.2% of cases. Arteries were affected in two patients (2.7%). Prevalence of individual platelets glycoprotein mutations did not differ between controls and study group. In both groups platelets glycoprotein polymorphisms moderately pro-thrombotic A1/A2 and C/T dominated, and the least numerous were strongly pro-thrombotic A2/A2 and T/T.Our results did not show the causative relationship between the existence of platelets GP IIIa/GP Ia mutations and venous system thrombosis in the women in labor. Probably presence of pro-thrombotic mutations of platelets glycoprotein in this group of patients does not represent the increased risk of thrombosis.