Premenstrual syndrome (PMS) is a condition that occurs during the premenstrual phase of the menstrual cycle. The cause is unclear but theories include: abnormal hormone levels, other biochemical abnormalities, inappropriate diet, nutrient deficiencies, psychological factors, or a combination of many factors.
Emotional and mental symptoms include fatigue, mood swings, irritability, nervousness, confusion, depression, tearfulness, and anxiety. Physical symptoms are bloating, discomfort, breast tenderness, cravings, weight gain, acne, change in bowel movements, joint pains, and dizziness.
Other menstrual problems
A missed period can be caused by pregnancy, stress, increased exercise, emotions, grief, and illness, among others.