Premenopause - This is the stage where a woman has no symptoms of perimenopause or menopause. She will still have periods and is medically considered to be in her reproductive years.

Perimenopause - As a woman gets closer to her 40s, her periods may become irregular (heavier/lighter, more spaced out), and her hormones (estrogen, progesterone and testosterone) begin to decline in an irregular way. She may also start to notice changes in her physical, mental, and emotional health – these are common signs of perimenopause, which can last for 7-10 years.

Menopause - Menopause is defined as the threshold at which a woman has gone 12 consecutive months without a period.

Postmenopause - This consists of the years that follow, once a woman has crossed the menopause threshold. At this point, symptoms may change, ease, or cease entirely. A woman spends the rest of her life in postmenopause.