Premenstrual syndrome (PMS) is a group of physical, emotional and behavioral symptoms that commonly occur in the two weeks prior to menstruation. It is common among women of childbearing age and symptoms usually recur in a predictable pattern. Some women experience symptoms so severe that they interfere with daily activities. These women have a condition known as premenstrual dysphoric disorder (PMDD), which is diagnosed under specific criteria established by medical authorities. Though the symptoms are similar, PMDD is considered a separate disorder from PMS.

The exact cause of PMS is unknown, although there are several factors that appear to contribute to its occurrence. Some women are particularly sensitive to the normal fluctuations of hormone production during the menstrual cycle, and others react to the changes in serotonin, a brain chemical that affects mood. Women with vitamin deficiencies and those that consume excessive salt, sugar, caffeine or alcohol may also experience PMS symptoms more frequently.

A number of factors have been identified that put women at a greater risk for PMS. Women with a family history of PMS and those with a history of depression or postpartum depression have PMS more frequently.

There are more than 150 symptoms attributed to PMS, but most fall into one of two categories, physical or emotional/behavioral. Some of the most common physical symptoms are abdominal cramps, breast swelling, breast tenderness, fatigue and bloating. Some of the most common emotional/behavioral symptoms are irritability, hostility, aggressive behavior, anxiety and depression.

There are no tools or tests that can be used to conclusively diagnose PMS. Rather, physicians determine whether an underlying medical condition is causing symptoms. If a medical condition cannot be found, then physicians recommend patients keep a menstrual diary to identify the type of symptoms experienced and track when they occur during the menstrual cycle. If symptoms occur in a predictable pattern in the two weeks before menstruation and then cease when menstruation begins, PMS is diagnosed.

PMS is treated in a variety of ways. First, physicians may recommend lifestyle changes such as eating a well-balanced diet, taking vitamins, exercising and reducing stress. Both over-the-counter and prescription medications are used in patients with more severe symptoms.

Because its cause is unknown, there is no known way to prevent PMS. However, making lifestyle changes can help prevent or reduce the severity of symptoms. Because PMS is directly linked to menstruation, the condition stops at menopause (the natural cessation of menstruation).