Premenstrual syndrome (PMS) is the name given to the physical, psychological and behavioural symptoms that can occur in the two weeks before a woman's monthly period. It's also known as premenstrual tension (PMT).
There are many different symptoms of PMS, but typical examples are:
- bloating
- breast pain
- mood swings
- feeling irritable
- loss of interest in sex
These symptoms usually improve when your period starts and disappear a few days afterwards.
Nearly all women of childbearing age have some premenstrual symptoms, but women in their late 20s to their early 40s are most likely to experience PMS.
Around 1 in every 20 women have symptoms that are severe enough to stop them living their normal lives. This is often the result of a more intense type of PMS known as premenstrual dysphoric disorder (PMDD).
The exact cause of PMS isn't fully understood. However, it's thought to be linked to the changing levels of hormones in the body during a woman's menstrual cycle.
The fact that PMS improves during pregnancy and after the menopause, when hormone levels are stable, supports this theory.
Certain lifestyle factors are also thought to aggravate the symptoms of PMS, including:
- lack of exercise and being overweight
- stress
- a poor diet