Pre-menopause is known as per menopause, the period before menopause sets in. This stage can last anywhere from 10-15 years before menopause. The first and most prominent symptom of perimenopause is a chance in menstrual cycle. This means your cycle changes in length. Discovery Health (2011) notes that three consecutive months with changes in the length of your cycle - for example from 25 days to 35 days - is a directly indication of perimenopause. Other symptoms include sleep disturbances, weigh loss or gain, mood swings, and changes in skin.