Abstract: Objective To compare the coagulation and fibrinolytic system features in patients with polycystic ovary syndrome (PCOS) and healthy women at the third trimester of pregnancy. Methods Eighty pregnant women who underwent routine obstetric examination in Outpatient Department of Obstetrics and Gynecology of Navy General Hospital from April 2012 to March 2013 were divided into PCOS group and normal pregnant group (40 in each group). Their coagulation and fbrinolytic system markers at the third trimester of pregnancy (≥ 37 weeks) were detected. Results The activity of coagulation factor Ⅷ (FⅧ) and coagulation factorⅩ (FⅩ) and the levels of von Willebrand factor (vWF), plasminogen activator inhibitor 1(PAI-1) and D-dimer were significantly higher while the tissue plasminogen activator (t-PA) level was significantly lower in PCOS group than in normal pregnant group (P< 0.05). Conclusion The level of coagulation is signifcantly higher while the levels of fbrinolytic system markers are signifcantly lower in PCOS patients than in healthy women at the third trimester of pregnancy.