Abstract

Background and Objectives: Whether oral contraceptives (OCs) use represents a predisposing condition for arterial ischemic stroke is controversial. In particular, few data are available on what criteria should be adopted to establish an individual profile of risk before the start of OCs.

Patients and Methods: The effect of OCs and their interaction with the G1691A polymorphisms of the factor V gene, the G20210A polymorphisms of the prothrombin gene, and the C677T polymorphisms of the MTHFR gene on the risk of cerebral ischemia were determined in a series of 108 consecutive women with ischemic stroke aged <45 years and 216 controls, in a hospital-based case-control study design.

Results: OCs use was associated with an increased risk of cerebral ischemia (OR=3.95; 95%CI 2.29-6.78). ORs for stroke were 2.25 (95%CI 1.15-4.40), 3.94 (95%CI 2.28-6.81) and 8.87 (95%CI 3.72-21.1) for non-OCs users with the TT MTHFR genotype, OCs users without the TT MTHFR genotype and OCs users with the TT MTHFR genotype, respectively, when compared to non-OCs users without the TT MTHFR genotype, with a multiplicative independent effect. Compared with non-OCs users, ORs for stroke were 2.65 (95%CI 1.46-4.81) for OCs users with none of the studied polymorphism and 22.8 (95%CI 4.46-116.0) for OCs users with at least one of the studied polymorphisms, with a synergistic effect.

Conclusions: Exposure to the effects of OCs may increase the risk of ischemic stroke in women with an inherited prothrombotic state. Testing for these genetic variants may allow a more accurate stratification of the population at risk before a long-term use of OCs is prescribed.