Perimenopause is the time of a women’s reproductive life when periods begin to change, along with hormone levels. In the early menopause transition cycles become closer together. When the interval between cycles become shorter, the amount of flow may vary. Checking hormone levels will yield variable results. The later perimenopausal period is marked by an absence of the menstrual cycle for at least one 60 day period. If this occurs in the early 40's, it is likely that menopause will occur on the early side. In this stage, the interval between cycles is very unpredictable. Hormone levels vary widely, and ovulation is erratic. Menopausal symptoms may occur, especially when cycles become more unpredictable. Menopausal symptoms will most often occur during long periods of anovulation, or several days before a menstrual cycle, when estrogen levels have declined. These changes often occur 2-7 years prior to the last menstrual cycle. If an FSH (follicular stimulating hormone) level is checked, it can vary widely from normal to menopausal levels, but a value of about 25IU/L if a very good indicator of the late perimenopause.
Menopause is actually the rest of your life after your last menstrual period.
When a woman says, “I am going through menopause,” she usually is referring to the changes that occur as hormone levels decline and symptoms occur, but this is really not correct. Menopause begins the day after your last menstrual cycle is over, and continues for as long as you live. Many women now live more than 40% of their lives in menopause. Physiologically, menopause is the cessation of ovarian follicular function. Every women is born with about 4,000 eggs, and she uses about 400 of them during ovulation throughout her reproductive years. Many of the eggs go through a process of atresia, or cellular death. The average age of menopause is 51, but normal menopause can occur as early as age 40 and as late as age 58.
Menopause can be induced surgically, or chemically. Surgical removal of the ovaries can occur at the time of hysterectomy because of disease, or chemotherapy can temporarily or permanently cause cessation of ovarian function.