Objective: The aim of the study was to detect the incidence of resistance to activated protein C in pregnant or puerperal women with confirmed diagnosis of deep venous thrombosis or pulmonary embolism. Design: Case-control study. Setting: Dept. of Obstetrics and Gynaecology, Dept. of Haemato-oncology, Medical Faculty, Palacký University, Olomouc. Methods: The group of 33 women with confirmed deep venous thrombosis were examined for resistance to activated C protein. The levels of C and S proteins, antithrombin III., prothrombin, heparin II cofactor and plasminogen were measured. Patient with APC ratio below 1.86, were tested by PCR analysis for the detection of the FV:Q506 allele. The control group had 51 pregnant women, chosen randomly. The statistical evaluation was performed by STATISTICA program. For the analyzing of the continuous variables the Students’ T-test was used. For the categorical variables the
2 test was used (for comparison of 2 relative values). Values below P<0.01 were considered to be statistically significant. Results: Women who have shown to suffer from deep venous thrombosis (DVT) came to the mean age of 31 ± 3.1 years, weight 75.3 ± 7.9 kg and BMI 28.7 ± 4.3. All of the results above were rendered to be statistically significant. 54.5% of thrombosis occured in the 3rd trimester, 61% were localised to the left iliofemoral vein. APC resistance appeared in 17 (51%) women with DVT, in comparison to 5 (9.8%) women in the control group (i.e. statistically significant). Factor V appeared in II (33.3%) women, in comparison to 3 (5.9%) women in the control group. Conclusion: APC resistance and factor V. Leiden represent as important factors in the aetiology of deep venous thrombosis in pregnancy.

        Key words: thrombosis, pregnancy, thrombophilia