RecruitingBehavioural interventionHow Hormones and Exposure and Response Prevention (EX/RP) Affect the Brain of People With OCDStudies show that hormones affect the brain's fear extinction network, which is relevant for therapy involving exposure and response prevention (EX/RP), a first-line treatment for obsessive compulsive disorder (OCD). This study will examine the effect of delivering EX/RP to women during different phases in their menstrual cycle to determine the effects of hormones on the fear extinction network and on their OCD symptoms.