The clinically relevant exposure period considered for data analysis will be the year preceding the index date, and exposure to domperidone will be classified according to prescriptions dispensed during this time period. For all cases and their matched controls, the investigators will identify all prescriptions for domperidone from the computerized medical records during the year prior to the index date. Current exposure to domperidone will be defined as a prescription dispensed within 30 days before the index date (35 days for Saskatchewan). Recent use, past use, and no use will also be explored as mutually exclusive exposure categories. Recent use will be defined as a prescription dispensed between 31 and 90 days before the index date, and past use as a prescription dispensed between 91 and 365 days before the index date. No use will be defined as no prescription of domperidone in the year preceding the index date and will be the reference category.