Menopause and menopause-related issues are appearing more frequently in the media. As part of this we are hearing more about perimenopause. Many women are uncertain about what this term actually means, so it seems timely to go into more depth about this stage of the menopause transition. In the next few posts I will explain in more detail what perimenopause is, how it affects women in the short and long term, and what steps women should do to take care of themselves during this period of their lives.
What is perimenopause?
Perimenopause is a variable period of time that occurs before menopause. Menopause is defined as the final menstrual period. At some point prior to this, the menstrual cycles stop coming at regular intervals and this is the point that defines the start of perimenopause. This can last anywhere from a couple of years to ten years. During perimenopause the menstrual cycles generally get further and further apart and can change in character; sometimes women will have intermittent spotting; sometimes unusually heavy bleeding.
What brings on the perimenopause?
Perimenopause is triggered when the supply of eggs in the ovaries reaches a critically low level – about 2,000. This is a drastic reduction from the time of birth, when the ovaries initially contained two to three million eggs! These eggs remain dormant until puberty. During puberty some of the eggs begin to mature and then one egg a month is selected to be ovulated and this initiates the onset of menstrual periods. A woman ovulates only about 400 times during her lifetime meaning that the rest are never used. These unused eggs gradually disappear through a process we don’t fully understand.
As the number of eggs remaining in the ovaries dwindles, the process of ovulation takes longer and longer and this is what causes the menstrual cycles to lengthen. Some months ovulation doesn’t even occur. Eventually there are no eggs available to ovulate and the final menstrual cycle occurs which marks the point of menopause.
When does perimenopause occur?
As noted, perimenopause starts several years prior to menopause. Since the average age of menopause is 52, most women will begin perimenopause between ages 42 and 50. However keep in mind that 5% of women will have menopause before the age of 45, so up to 5% of women may well find themselves in perimenopause in their 30’s.
How are the hormones affected?
In the ovaries, each egg is surrounded by specialized cells called follicular cells. These are the cells that produce estradiol and progesterone. Therefore, as the number of eggs decline, the hormone levels decline because the follicular cells are no longer available to make the hormones. However, the decline in estrogen and progesterone doesn’t occur in a predictable linear fashion. As noted in the accompanying chart, 
during perimenopause the peak estrogen levels zig-zag downward haphazardly. In the early phases, sometimes the estrogen level will be nearly normal, but then it dives downward. In the latter part of perimenopause the levels continue to fluctuate downward until they finally bottom out at the time of menopause.
In addition, the progesterone levels decline – sometimes in accordance with the estrogen, sometimes in the opposite direction. The decline and mismatch of our hormones causes an array of symptoms that can come and go throughout perimenopause and vary in severity.
What issues do women experience in perimenopause and why do they occur?
Many women are blindsided by the myriad of symptoms that are brought on by perimenopause. It is a time when women experience major changes in the menstrual cycle, how they feel, and how they sleep. It is also a time when changes that impact their general health occur. These changes occur because estradiol plays a role in just about every organ system in the body. It would take an entire book to explain all of these (which is why I wrote my book, The Estrogen Question: Know Before You Say NO to HRT). But for this blog I will summarize the organ systems that are impacted the most.
The reproductive system
As noted, the number of eggs available for ovulation declines over time. This causes problems with fertility. In fact, the chance of having a successful pregnancy once a woman is in perimenopause is less than 15%.
Without estrogen stimulation, the reproductive organs (ovaries, uterus, breast glands) shrink in size. In addition, the cells making up the tissues in the pelvic area also diminish in size and function. This causes the vagina and surrounding tissue to become drier and more fragile, leading to itching, discomfort, and loss of elasticity. Over time women can develop pain with intercourse, bladder leakage, and an increased risk of vaginal and bladder infections.
The brain
Estrogen plays a major role in keeping the brain cells (neurons) healthy. It helps supply them the fuel they need (which is
glucose), it helps the neurons communicate with each other, and helps in the production of the brain chemicals (neurotransmitters). Estrogen is also a powerful anti-inflammatory agent and anti-oxidant. When the estrogen level goes down, many areas of the brain simply do not function normally. For an in-depth review of estrogen and the brain, see the webinar I produced with menopause coach, Nathalie Bonafé.
Some areas of the brain are more affected by the loss of estrogen than others. One area is the hypothalamus, which regulates all of our body systems, including temperature, sleep and energy balance. Dysfunction in the hypothalamus is what is responsible for the hot flashes, and sleep disturbance – two problems which affect almost all women during perimenopause. Since the hypothalamus also regulates energy expenditure, women find that they gain weight without any obvious change in their activity and intake.
Estrogen deprivation affects areas of the brain that regulate mood. Thus it is very common for women to experience mood
changes such as anxiety, irritability and depression during perimenopause. Other parts of the brain that rely on high estrogen are areas involved in cognition. When these areas don’t function optimally women can experience problems with their memory, concentration and problem solving – a spectrum of symptoms known as perimenopausal brain fog.
The bones and muscles
The bones and muscles are dependent on estrogen to maintain good strength. When the estradiol declines, our bones are broken down at an accelerated rate. Women can lose about 1% of their bone mass per year during perimenopause. This accelerates the chance of developing osteopenia which is the term for thin bones. Women who have osteopenia have a higher risk of developing osteoporosis prematurely, which leads to hip and back fractures.
Lean muscle mass also starts to decrease. Women may note a decrease in their strength and endurance and this may also predispose them to a greater chance of muscle strain and injury.
The blood vessels and heart
Estrogen helps keep the blood pressure and cholesterol low and helps keep the lining of the arteries healthy. During perimenopause, the decrease in estrogen causes plaque to build up in the arteries at an accelerated rate. This increases the risk of a heart attack and stroke down the line. This explains why women have a lower risk of heart disease than men until they go through menopause. At that point men and women have the same risk.
Body fat and metabolism
Estrogen prevents fat from being deposited around the abdomen. When the estrogen level drops during perimenopause fat begins to appear around the middle, causing the unwelcome accumulation of belly fat. This fat is also deposited inside the abdomen, in and around our organs. This is called visceral fat. Visceral fat is unhealthy fat and is associated with an increased risk of heart disease, diabetes and other harmful health conditions.
The bottom line
All of these effects due to the loss of estrogen are changes that can jump start the chance of a number of chronic diseases down the line – such as heart disease, osteoporosis, diabetes and possibly even Alzheimer’s disease. That is why it is important for women to be aware of these changes and be as proactive as possible to counteract them.
What should women do to take care of themselves during perimenopause?
The challenge women face is addressing what they should do to take care of themselves during this transition. Recognizing that these changes will occur is the first step. Developing a strategy to deal with the changes is the next step. My next two blogs will focus on this subject, including lifestyle measures, hormonal treatment and non-hormonal medication options.
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