It is not clear why some women are affected by PMS and others are not, or how the symptoms of PMS are caused. However, PMS is believed to largely occur as a result of the changes in the levels of oestrogen and progesterone that occur during the luteal phase of the menstrual cycle, which commences at the time of ovulation (usually the 14th day after the start of menstruation if your cycle is 28 days).
Other hormones may also be involved (for example, some symptoms, such as breast tenderness, have been linked to an excess of prolactin, a hormone that stimulates the production of breast milk).
Mineralocorticoids are a group of hormones that regulate the body’s fluids. Changing levels of these hormones may cause the fluid retention and bloating that many women experience. Similarly, hormonal imbalance may affect levels of neurotransmitters such as serotonin, and this may lead to emotional symptoms such as anxiety and depressed mood.
The symptoms of PMS may be aggravated by a wide range of factors, including stress, genetics, the number of children you’ve had, underlying physical or health problems (e.g. underactive thyroid, depression), and exposure to compounds called xeno-estrogens, which are present in our environment (e.g. from some pesticides).
Additionally, a number of dietary factors appear to influence PMS symptoms. These include:
- High dietary intake of salt, which is especially linked to fluid retention
- Consumption of excessive quantities of sugar, alcohol and/or caffeine, which are linked to disturbed moods and energy problems. Blood sugar imbalance may also be a factor for some women.
- High fat diets, especially those high in saturated fat
- Low intake of magnesium and calcium
Regular exercise appears to offer a degree of protection from PMS, and is associated with less susceptibility to both emotional and physical symptoms.