Hormone levels may begin to change in your 30s, as you enter perimenopause -- the interval in which your body begins its transition into menopause.

In the years leading up to menopause, small hormonal imbalances can exist, so by the time menopause begins, you may have already experienced close to 20 years of hormonal imbalance.

Perimenopause and menopause hormone imbalance can be marked by a variety of symptoms, notably:

* weight gain and hot flashes;

* night sweats and insomnia;

* mood swings and anxiety;

* depression and foggy thinking;

* memory changes and headaches;

* menstrual irregularities and vaginal dryness;

* decreased libido and dry skin; in addition to

* fatigue.

These symptoms of hormone imbalance are caused primarily by an incorrect relationship between the two main female hormones progesterone and oestrogen in the body. They, along with other hormones DHEA (dehydroepiandrosterone) and testosterone exist in a delicate balance, each performing a unique biological function. Variations in that balance can have a dramatic effect on your health, resulting in symptoms of hormone imbalance.

The amounts of these hormones produced by your body can vary depending on factors such as stress, nutrition, exercise and ovulation. When the balance between oestrogen and progesterone is thrown off in favour of oestrogen, a woman may become "oestrogen dominant". This condition is associated with a number of conditions, including endometriosis, uterine fibroids, polycystic ovaries, and breast cancer. Oestrogen dominance can occur in any woman, but perimenopausal women, who typically experience a more rapid decline in progesterone than in oestrogen, are especially at risk.