Premenstrual syndrome (PMS) is the name given to the set of physical, psychological and emotional symptoms that appear in the days leading up to a woman's monthly period. It's also known as premenstrual tension (PMT). Usually, the symptoms improve when the woman's period starts and disappear a few days afterwards.

Nearly all women of child-bearing age have some premenstrual symptoms, but those between their late 20s and early 40s are most likely to experience PMS. A small number of these women will have symptoms severe enough that they disrupt their daily lives. PMS usually improves after the menopause.

The exact cause of PMS is not fully understood. However, it's thought to be linked to the changing levels of hormones in the body during a woman's menstrual cycle.

There is no cure for PMS, but there are treatments available and changes that can be made to help women manage their symptoms.