Premenstrual syndrome (PMS) is a set of physical and emotional symptoms that appear in the one to two weeks before a period. The symptoms usually ease once the period starts.
PMS symptoms differ from person to person and from month to month. Common ones include:
The exact cause of PMS is not fully understood. Symptoms are linked to the rise and fall of hormones such as estrogen and progesterone in the luteal phase, the second half of the cycle. Some people seem more sensitive to these changes than others. Diet, sleep and stress may affect how strong symptoms feel, and some people look at PMS and nutrition together.
A small number of people have a severe form called PMDD (Premenstrual Dysphoric Disorder), where mood symptoms are intense enough to disrupt daily life. Keeping a symptom diary for two or three cycles can help a GP see the pattern and discuss treatment options.
Tiredness, poor sleep and low mood can make focus harder for a few days each month. Flexible hours, the option to work from home and short breaks can help people manage these days without taking sick leave.
Sources: NHS, MedlinePlus.