Do birth control pills and IUDs raise the risk of a rare brain pressure disorder?A large, new study offers some reassurance for millions of women using hormonal contraception.Researchers analyzed 13 investigations involving more than 670,000 women with an average age of 33. About 53-hundred had the disorder called idiopathic intracranial hypertension, or IIH.Their analysis found no association between hormonal contraception --including birth control pills, IUDs, implants, injections, and patches—and IIH.IIH occurs when pressure builds up in the fluid around the brain with no apparent cause. It can lead to severe headaches, ringing in the ears, and sometimes vision loss.It most often affects women in their reproductive years, particularly those with obesity—and its exact cause is still unknown.For years, concerns have lingered about whether hormonal birth control might play a role.One study author says, “Our findings can provide reassurance that using hormonal contraception may not be linked to this condition.”He says more large, well-designed studies are needed, particularly in diverse patient groups, to confirm these results.Source: NeurologyAuthor Affiliations: University of Toronto .Sign up for our weekly HealthDay newsletter