text: Premenstrual syndrome (PMS) is a group of symptoms related to the menstrual cycle. PMS is linked to changes in the endocrine system, which produces hormones that control the menstrual cycle. Medical experts don't fully understand the chain of events that causes premenstrual symptoms to be severe in some women and not in others. The one direct cause that is known to affect some women is genetic: Many women with PMS have a close family member with a history of PMS.