Contraception is an important health issue in preventive medicine because it protects women globally from the effects of unwanted pregnancy and allows them to integrate into society. The mechanism by which COCs predispose these events remains unclear. This research priority included efforts to discover the effect of COC (DUOFEM) on haemostatic parameters and possible mechanism of actions in female wistar rats.Eighty (80) female wistar rats weighing 180-250 g were used for the study. They were divided into four groups of 20 rats each comprising 10 treated and 10 control rats.The treated groups received COC (DUOFEM) 0.6 mg/kg body weight intragastically for 36, 48, 60 and 72 days in 5-day cycles (4-day treatment with a 1-day break).An enzyme-linked immunosorbent assay (ELISA) was used for the quantitative determination of Protein C and S Antigen in citrated rat plasma. Antithrombin (AT) was determined by Chromogenic Assays.Prothrombin time (PT), Activated partial thromboplastin time (APTT) were performed using Sysmex CA-6000 Coagulation Analyzer. There were significant decreased inprothrombin time (PT), fibrinogen (Fib), antithrombin (AT), protein C (PC) and protein S (PS) in all treated groups compared to controls(P<0.001).There were however no significant changes in activated thromboplastin time (APTT).This study has challenged the concept that reducing doses of both estrogen and progesterone in COCs may eliminate the risk associated with their use. Even at the lowest concentration of estrogen and progesterone in DUOFEM, the safety of COC is yet to be achieved. COC users should be monitored for haemostatic parameters.