Menopause usually starts in our mid-40s and this is known as peri-menopause. Periods start to fluctuate as reproductive hormones decline.  Women are considered to be in menopause when their periods cease.  From my database of 500,000+ women who have completed the MyMT Symptoms Quiz I can tell you that on average this happens at 51 years of age.  After one year of periods ending, women enter post-menopause where they remain for the rest of their lives. We live nearly half of our life in a completely different hormonal environment, so we need to know how to adjust to this.