PROS1 and polycystic ovary syndrome: Prothrombin levels were decreased in PCOS (161,458 ± 1275 vs 165,233 ± 1958 RFU, p < 0.05) and the anticoagulant vitamin K-dependent protein S (4403 ± 69 vs 3989 ± 59 RFU, p < 0.0001) and heparin cofactor II (HCII) (4156 ± 64 vs 3821 ± 63 RFU, p < 0.001) were increased (Fig. 2).