Hormones.Your hormone levels throughout the menstrual cycle hit highs and lows. This affects your brain and the signals it transmits to the body which can cause or contribute to premenstrual syndrome.

Brain chemistry.Some experts claim that lack of a brain chemical, serotonin, results in PMS, and in extreme cases, depression.

Thyroid problems.If your thyroid gland malfunctions, you’ll experience PMS-style symptoms – so make sure your doctor establishes exactly where the problem lies.

Vitamin and mineral deficiencies.Vitamins B6 and D and minerals like calcium and magnesium are thought to reduce symptoms of PMS – a daily vitamin supplement is a bright idea if you suffer badly.