N94: Pain and other conditions associated with female genital organs and menstrual cycle

N94.3: Premenstrual tension syndrome

This lining of the uterus thickens at the start of each normal menstrual cycle. It is then expelled when you have your period. This process is controlled by various sex hormones.

You can have various symptoms in the period before your menstrual period. You may have pain in your lower abdomen or lower back, for example. Your breasts may also swell up and feel heavy and tender. You may also have headaches. You may also have low mood or mood swings.