Effect of low dose oral pill on haemostatic parameters in a set of Pakistani population.

OBJECTIVE To observe the adverse effects of low dose combination contraceptive pills on blood coagulation in a set of local population. METHODS Between December 2002 to December 2003 a comparative cross-sectional study was conducted at the Department of Pharmacology, Ziauddin Medical University, Karachi and Aga Khan University Hospital, Karachi. Fifty women of reproductive age were divided in two equal groups; one being the users of combination oral contraceptive pills (ethinyl estradiol and levonorgestrel) and the other being matching controls not taking any hormonal contraceptives. We studied, CBC, PT and INR, APTT, BT and platelet aggregation against ADP, collagen, epinephrine and ristocetin. RESULTS PT, INR, and platelet aggregation response to ADP, collagen, epinephrine, and ristocetin were not significantly different among the groups. However, APTT was shortened in users of contraceptives (p = 0.003). CONCLUSION The referred oral contraceptive is associated with enhanced activity of intrinsic pathway of secondary haemostasis.