Abstract
Background: The pharmacotherapies varenicline, bupropion and nico-tine replacement therapy (NRT) are the most effective strategies forsmoking cessation. Prior studies of these medicines in pregnancy havenot been adequately powered to generate clear evidence on the riskof congenital malformations.Objectives: To assess the risk of major congenital malformations(MCM) associated with exposure to varenicline, NRT and bupropion(for smoking cessation) in the first trimester.