When women hit their late thirties or early forties, many begin the process of perimenopause, a highly variable period of time when the reproductive cycle begins to shorten, eventually starts to skip (usually around age forty-seven), and then finally comes to a halt with menopause (average age fifty-one). The term perimenopause is more of a description than it is a true developmental state. It is a time of transition from full fertility into menopause.
The average age of perimenopause onset is within a broad range, between thirty-nine and fifty-one (but it can start anywhere after age 25, the peak age of fertility) and is highly unpredictable with respect to any individual woman. How and when perimenopause appears is an inexact process; its symptoms vary month-to-month and even day-to-day. Often the earliest sign is the shortening of the monthly cycle. You still will have your period, but you may notice that it comes sooner, is heavier and/or shorter. You may skip some months. You may also notice physical changes reflecting changing ratios of hormones.
These changes are the result of the aging and declining number of remaining follicles, or eggs, in the ovary. The ovaries are somewhat like an hourglass of sand, with the follicles (eggs) being represented as the grains of sand. The hourglass is turned over even before we are born, and the follicles begin to slip away. As we age, the “sand” begins to run out and the volume left behind is less, affecting the end mix of the hormones generated by the remaining follicles. Thus, the lessening of hormonal power becomes more evident. Usually this takes place in the early to mid-forties, but even earlier for some women.
