Yes, there are several medical contraindications to diving. Some are temporary, such as pregnancy, others are definitive and formal, such as asthma and bronchial hyperreactivity. The complete list of these contraindications is available on the FFESSM Medical Commission website. You should be aware that sinus, dental or ear problems must be treated before diving. The FFESSM license is only issued upon presentation of a medical certificate of no contraindication to scuba diving. This certificate is issued after an examination by a doctor, to avoid any further inconvenience.