Oral contraceptive misuse as a risk factor for cerebral venous and sinus thrombosis

Background: Consumption of oral contraceptive pills (OCP) is a known risk factor for cerebral venous and sinus thrombosis (CVST) among women. We determined whether misuse of OCP could increase the risk of CVST in women. Methods: A case-control study was conducted from 2003 to 2007 on 64 female patients with CVST admitted to Al-Zahra medical center and 232 healthy age-matched female OCP users as controls. Patients and controls were interviewed and misuse of OCP was categorized to taking OCP for self-treatment of dysfunctional uterine bleeding, for family planning without physician consult, or for delaying menstruation in purpose of religious customs or traveling, and taking OCP in high dose during the preceding year. Results: Among 64 cases and 232 controls, 30 (46.9 %) and 63 (27.2 %), respectively, had a history of OCP misuse (Odds Ratio = 2.36, 95% Confidence Intervals = 1.33 to 4.18, P = 0.002). Also, using cyproterone compound (Diane) was more frequent in the CVST group (P < 0.001). Multivariate analysis controlling for age, OCP misuse, type of OCP, and history of coagulopathy showed that OCP misuse (P < 0.001) and using Diane as the OCP (P = 0.006) were both independently associated with CVST. Discussion: OCP misuse can be considered as an additional predisposing factor for CVST among women and partly responsible for larger proportion of female patients with CVST. These findings should alarm the healthcare system to create strategies controlling the inappropriate use of OCP among Iranian women.