Oral contraception and epilepsy: findings in a large cohort study.

There is no good evidence that oral contraceptives (OCs) increase the risk of epilepsy in unaffected women or increase the frequency of seizures in those suffering from the disorder. Nonetheless, manufacturers' literature continues to include warnings about OCs and epilepsy. We have analyzed the available data about epilepsy in the Oxford-Family Planning Association contraceptive study that includes 17,032 women followed for periods of up to 26 years. In total, 82 women (with no record of having suffered epilepsy when recruited to the study) were referred to hospital for diagnosis or treatment of epilepsy during the follow-up period. No association was found between OC use and the occurrence of the condition. Referral to hospital was, however, more frequent in women of low social class and in those with a high body mass index.