Although many investigations into the onset of obsessive-compulsive disorder (OCD) suggest the occurrence of potential life events as triggering factors, such an association has not been well studied to date. The purpose of the present paper is to review the literature on OCD onset in order to determine whether OCD is triggered by recent life events, what specific events may serve as triggers, and the clinical and research implications of these factors. Overall, the available studies do not consistently support the theory that OCD is triggered by specific antecedent life events. However, there is a body of evidence to support the theory that the specific life events of pregnancy and birth of a child can trigger OCD. This apparent association has led to the investigation of certain neurohormonal factors, including changes in estrogen or oxytocin levels, that may be of etiopathogenetic significance in OCD. Confirming such associations may allow clinicians to provide more targeted preventive and therapeutic interventions.