The National Institutes of Health defined premenstrual syndrome (PMS) as physical and psychological symptoms that arise about a week to 10 days before women get their monthly period.
The Mayo Clinic reported an estimated three of every four menstruating women experience some form of premenstrual syndrome. This tends to peak during the late 20s and early 30s. NIH added PMS symptoms typically get worse as women approach the transition to menopause.
WomensHealth.gov wrote PMS is different for everyone. Most women have fairly mild symptoms while small amounts have a severe form of PMS, called premenstrual dysphoric disorder (PMDD).
University of Maryland Medical Center (UMMC) said while the exact cause of PMS is unknown, popular theories include hormonal changes such as too much estrogen or not enough progesterone, low levels of vitamin B6 or other nutrients, abnormal metabolism of hormone-like substances called prostaglandins, and low levels of the brain chemical serotonin.
WomensHealth.gov said PMS can cause both emotional and physical symptoms. These include acne, swollen or tender breasts, fatigue, insomnia, upset stomach, constipation, or diarrhea, headache or backache, appetite changes or food cravings, joint or muscle pain, trouble with concentration or memory, tension, irritability, mood swings, crying spells, anxiety or depression and weight gain due to fluid retention.
NIH said other symptoms are poor judgment; feelings of guilt, increased fears; slow, lethargic movement; less tolerance for noise and light and changes in interest in sex.
Although this list of symptoms is long, the Mayo Clinic said most women with PMS experience only a few.
WomensHealth.gov cautioned PMS symptoms usually disappear after the bleeding starts, but sometimes continue for the first few days of the period.
PMS treatment options include lifestyle changes, medications and alternative therapies.
For mild PMS, WomensHealth.gov said lifestyle changes include regular exercise, eating healthy; avoiding salt, sugary foods, caffeine, and alcohol; not smoking; and getting enough sleep.