Hormonal Update Volume 2 Number 5

Defining Perimenopause

In recent years the scientific and medical communities have come to understand a whole new dimension in a woman’s hormonal landscape -perimenopause. Perimenopause is the time leading up to and immediately following menopause, and literally means `surrounding menopause’. Technically, menopause is an event that occurs 12 months after a woman’s last menstrual cycle. Generally occurring during a woman’s forties, perimenopause can begin as early as age 35. 

We now know that the changing of a woman’s hormonal profile over her lifetime is indeed a process. The age-related decline in the sex steroid hormones estradiol, progesterone, DHEA and testosterone is not as sudden as once believed. By the time a woman reaches her mid-forties her hormone levels have already begun to change substantially. (For a more comprehensive discussion of sex steroid hormones see HU Vol 1, No 1).

Over a rather lengthy period of time sex steroid hormones first begin to fluctuate, then fluctuate wildly, and then decline causing a number of physiological changes and symptoms. Ranging from subtle to dramatic, these often unexpected physical and emotional changes, such as hot flashes, insomnia, decreased libido, and mood swings, can be disconcerting. Without knowing the cause, a woman can become alarmed or begin to worry that something is wrong with her health. While hormonal changes are more dramatic in some women than in others, they are a normal part of the aging process. Understanding what causes physiological changes during perimenopause can help a woman make knowledgeable and informed choices about her lifestyle and healthcare. And, it can also help alleviate the fear that there is something wrong. 

The Physiology of Perimenopause

As a woman gets older the number of eggs in her ovaries begins to decline rapidly, and she begins to ovulate less regularly. Some months she may not ovulate, while during other months two eggs can be released instead of one, which may explain the increase in the number of twins born to women over forty.

During this time of hormonal changes, in an attempt to keep the ovaries functioning and the body’s estrogen level up, the brain increases its production of follicle stimulating hormone (FSH), the hormone that encourages the growth of follicles, the fluid-filled sacs that contain an egg. The brain also sends a message to increase production of luteinizing hormone (LH), which is released when blood levels of estradiol are low. 

During normal ovarian function, once an egg is released, progesterone production increases, preparing the uterine lining for implantation of the fertilized egg. If this occurs, progesterone then acts to help sustain the developing embryo. However, if there is no egg in the sac, which can happen during perimenopause, no progesterone is produced. 

As ovulation becomes more erratic, so do hormone levels. FSH, LH, estrogen and progesterone levels surge and drop, surge and drop, producing a kind of hormonal chaos. When hormone levels increase and decrease suddenly, physical symptoms may result. 

Symptoms of Perimenopause Are Highly Individual

Women are hormonal individuals, therefore every woman’s experience of perimenopause is her own. Not all women have symptoms, and even if they do, there are many different constellations. Some women may have hot flashes and insomnia but their menstrual cycles are not affected. Others may experience more of an emotional roller coaster, and yet others may have very erratic cycles with extreme changes in flow. There are almost as many ways of experiencing perimenopause as there are women who experience it. 

It is important to remember that the reason each woman can experience her own particular set of symptoms during perimenopause is that symptoms are caused by a woman’s own pattern of hormonal fluctuations. As you will see from the following chart, one woman’s hot flashes can be caused by a drop in her estradiol level, another’s by a drop in her progesterone level. One woman’s lack of interest in sex could be caused by vaginal dryness attributed to a decrease in her estradiol level, another woman’s by a drop in her testosterone level. Consequently, there is no standard of therapy that works for all perimenopausal women - no one-size-fits-all answer that suits all symptomatic women. 

Fine Tuning What is Right for You