Part I: A Woman’s Guide to Perimenopause: Signs & Symptoms, Hormonal Changes, Testing, & More

Published On: August 19, 2024

What is perimenopause, and when does it start?

Perimenopause is the hormonal transition before menopause, when estrogen, progesterone and testosterone begin to shift. It can start 7 to 10 years before your final period, often in your late 30s or early 40s. Common signs include irregular periods, hot flashes, poor sleep, mood changes, brain fog and weight gain. No single blood test confirms it, so diagnosis relies on your symptoms, cycle changes and history.

Written by Dr. Christine Maren, D.O., FMCP-M, MSCP, a board-certified physician and Menopause Society Certified Practitioner (MSCP). The research behind this article is cited throughout and listed in the sources at the end.

Perimenopause is finally getting the attention it deserves. And I’m here for it!

Yet, despite the increased attention, most women are surprised to learn how early perimenopause symptoms can start—as early as the late 30s and early 40s for most of us.

As a 40-something woman myself, I know this season of life can be challenging. The last thing we need to deal with is hormone issues.

I also know it’s a season of life when we can thrive. I’m living proof that this can be a time of growth when we learn to know and love our bodies and souls.

Recognizing the signs and symptoms of perimenopause early will help us get the care and treatment we need sooner so that we don’t have to suffer.

This is especially important for those with autoimmune disease, hypothyroidism, and other chronic health conditions, as they are associated with an earlier onset of symptoms.

Perimenopause care is important for quality of life; it can also help preserve women’s resilience, prevent disease, and enhance overall long-term health.

As I’ve expanded my knowledge and awareness on the topic, it’s also become evident that many women are misdiagnosed with conditions such as estrogen dominance during this phase when perimenopause is to blame (more on this to come).

If this resonates, there's more.

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In Part 1 of this article series, I am pulling back the curtain on the mysteries and misunderstandings about perimenopause, including:

What perimenopause is (and how it differs from menopause)
The age of onset
Signs and symptoms
Hormonal changes and the role of estrogen, progesterone, and testosterone
Tests for perimenopause (spoiler alert: there is no perfect test)
Impacts on physical, mental, and emotional health

But this is just the start! In subsequent articles, we’ll cover integrative management and treatment options—from supplements and lifestyle to the risks and benefits of Hormone Replacement Therapy (another spoiler alert: I’m an HRT advocate!)

Sadly, many women in my mother’s generation have missed out on the benefits of HRT, given the publicity behind the Women’s Health Initiative study in the early 2000s, which erroneously scared us all into thinking HRT causes breast cancer (more on this in a subsequent article).

Now, it’s our turn to empower the next generation of women with the knowledge and tools to protect and preserve our health during perimenopause and beyond.

What Is Perimenopause? Age Of Onset & How It Differs From Menopause

Perimenopause is the long transition to menopause characterized by hormone insufficiency and sometimes chaotic fluctuations in estrogen.

This transition can start 7-10 years before menopause and causes various symptoms, including:⁹⁴

Changes in the menstrual cycle, such as shorter or longer cycles, changes in flow, or missed periods
Weight gain
Anxiety
Irritability
Trouble sleeping
Heart palpitations
Hot flashes
Low libido
Muscle and joint pain
And these are just a few examples!

Menopause is a state of hormone deficiency that occurs after a woman has gone 12 consecutive months without a period (without other health conditions responsible for this). Menopause marks the end of our reproductive years, and it is characterized by a significant drop in estrogen and other hormone levels.

According to the US Department of Health and Human Services, the average age of menopause in the United States is 52.⁹⁶

The normal age range for menopause can vary between 45 and 58.

Early menopause occurs between the ages of 40 and 45.¹¹⁶,¹²¹

Premature menopause occurs before age 40.¹²²,¹²³

Also known as premature ovarian insufficiency (POI) or premature ovarian failure, it affects 1% of women under the age of 40. Premature menopause can be cause for concern because it increases the risk of premature death, neurological diseases, psychosexual dysfunction, mood disorders, osteoporosis, ischemic heart disease, and infertility.¹²⁷,¹²⁸

Quick math: if the average age of menopause is 45-58 and perimenopause starts 7-10 years prior, that means on average women will experience perimenopause between the ages of 35-48.

Just want to highlight again that perimenopause is a condition that affects most women in their late 30s or early 40s. But it can also happen earlier.

What Influences The Onset Of Perimenopause/ Menopause?

We know certain conditions and lifestyle habits can influence the onset of perimenopause/ menopause, including:

Smoking: Smoking can accelerate the onset of menopause up to two years. Women who smoke may also have more severe menopause symptoms, and smoking also worsens the effect of early menopause on mortality risk.¹²⁹,¹³⁰
Body Weight: Being significantly underweight can lead to earlier menopause due to lower estrogen levels. Women who are overweight with central obesity may also experience early menopause.¹³¹
Childbearing status: Women who have children later in life may experience menopause later. Conversely, menopause may happen earlier in women who have never had children.¹³²
Early menarche (onset of menses): Although not always the case, research suggests women who get their first period before age 11 have a higher risk of early menopause than women who get theirs after age 12.¹³³
Physical Activity: Regular exercise, particularly weight-bearing exercises, may delay menopause.
Race: Menopause tends to happen earlier for African American and Hispanic women and later in women of Asian descent.¹³⁵
Genetics: Family history plays a significant role; if a woman's mother had a later menopause, she might also experience menopause later.¹³⁶
Autoimmune Disorders: Certain autoimmune disorders can affect ovarian function, potentially leading to earlier menopause.¹³⁷
Underlying health issues, including hypothyroidism: Menopause may happen earlier in women with underlying health problems, including hypothyroidism. ¹³⁸
Hysterectomy: Women with a hysterectomy are also likely to experience menopause earlier, even if they still have ovaries (this is a big surprise because ovaries are still making hormones!).¹³⁹
Medical Treatments: Chemotherapy and pelvic radiation can induce early menopause.¹⁴⁰
Traumatic brain injury (TBI): Women with TBI may have disruptions in hormonal regulation and potentially an earlier onset of menopause.¹⁴¹
Alcohol consumption: There is a weak link between moderate alcohol intake and lower risk of natural early menopause.¹⁴² However, alcohol use is associated with more severe menopausal symptoms and increases the risk of other conditions like heart disease, cancer, and osteoporosis. During perimenopause, people who are already moderate-to-heavy drinkers are at greater risk for alcohol dependency/addiction.

A Note About Toxin Exposure and Menopause

As women become educated about their health, they often wonder if toxin exposure from common household items, plastics, and other pollutants may contribute to the onset of menopause.

The answer is yes!

Persistent exposure to endocrine-disrupting chemicals (EDCs) is associated with reproductive aging, earlier onset of menopause, and vasomotor symptoms like hot flashes in women.¹⁴³,¹⁴⁶,¹⁴⁹

EDCs are a broad category of chemicals that can interfere with the endocrine (hormonal) system. They can mimic, block, or alter hormone production, secretion, transport, binding, action, or elimination in the body.

Xenoestrogens are a specific type of EDC that mimics the effects of estrogen. The term "xenoestrogen" comes from "xeno," meaning foreign, and "estrogen," indicating that these are external compounds that act like estrogen in the body. Think of these as “bad” estrogens (just like good fats and bad fats).

Xenoestrogens can contribute to unopposed estrogen activity, which may increase the risk of conditions like endometrial hyperplasia or cancer. Prolonged exposure is also linked to an increased risk of breast and uterine cancer, as well as osteoporosis.¹⁵⁰,¹⁵²,¹⁵³

Heavy metals are another type of EDC that can impact our hormones. Exposure to heavy metals, including arsenic, cadmium, and mercury, can diminish ovarian reserve and lead to earlier onset of menopause.¹⁶⁰

EDCs are found in a variety of everyday products and environments, including plastics (like BPA and phthalates), pesticides (like DDT and atrazine), industrial chemicals (like PCBs), personal care products, and even some foods and packaging materials.

The good news is we can help mitigate our levels of exposure to these chemicals by making simple changes to our lifestyle and what we drink, eat, and use around our homes.

Download my Guide: 12 Ways to Detox Your Home for more detailed information and tips.

Understanding these factors can help women take steps to support their hormonal health and potentially delay the onset of menopause.

What are the signs and symptoms of perimenopause?

So many of us struggle with “hormone imbalance” in our 30s and 40s — fatigue, mood shifts, heavy cycles — only to be told it’s just stress, aging, anxiety, or that we need to eat less and exercise more.

In reality, perimenopause is often the culprit. Shifts in progesterone, estrogen, and testosterone can affect everything from your sleep and metabolism to your mood and menstrual cycle.

The tricky part? Symptoms don’t always look like the classic “hot flashes” we’ve been taught to expect. They can show up years earlier, in subtle ways, and are often dismissed or misdiagnosed.

That’s why I created a dedicated article: Early Perimenopause Symptoms: 10 Signs You Shouldn't Ignore in Your 30s and 40s — to help you recognize what’s really going on in your body.

How do estrogen, progesterone and testosterone change in perimenopause?

Let’s examine what happens with your hormones during perimenopause.

Understanding the balance of progesterone and estrogen is essential, as well as the role testosterone (yep) plays in women’s health.¹⁶¹,¹⁶²

Yes, other important hormones are involved during perimenopause, including thyroid, cortisol, insulin, and others. However, we’ll focus on progesterone, estrogen, and testosterone for this article and discuss the others in a future article.

I’ve used the symphony analogy regarding hormones before due to their intricate and coordinated functioning.

Just as a symphony requires the harmonious performance of various instruments under the guidance of a conductor to produce beautiful music, the endocrine system relies on the harmonious interaction of multiple glands and hormones to maintain the body's internal balance and regulate numerous physiological processes.

For example, the hypothalamus releases gonadotropin-releasing hormone (GnRH), stimulating the pituitary to release luteinizing hormone (LH) and follicle-stimulating hormone (FSH), which regulate the function of the ovaries and testes in reproductive processes.

Further, hormones' effects are determined not only by their circulating levels but also by the sensitivity and availability of their receptors.

This can make understanding how hormones work seem complicated, but I promise you can grasp this (and you’ll be better for it!).

Here are some important considerations to help you understand your hormones:

Production and secretion: Hormones are produced and secreted by endocrine glands (pineal, hypothalamus, pituitary, parathyroid, thyroid, adrenals, pancreas, ovaries, or testes) in response to specific stimuli. Factors like stress, nutrition, sleep, and physical activity can influence hormone production.
Circulating levels: The circulating concentrations of hormones depend on their bioavailability, which various factors can influence. For instance, the bioavailable/ free testosterone level will be influenced by levels of Sex Hormone Binding Globulin (SHBG).
Feedback mechanisms: Hormonal balance is maintained through feedback loops. For instance, high levels of thyroid hormones (T3 and T4) inhibit the release of thyroid-stimulating hormone (TSH) from the pituitary gland, reducing thyroid hormone production. Note that women lack feedback inhibition for high androgens (that’s for another article but relevant for women with Polycystic Ovarian Syndrome, or PCOS)
Hormone receptor sensitivity: This depends on receptor density (the number of receptors available) and receptor affinity (how strongly a hormone binds to its receptor).
Downregulation: Hormone receptors can be downregulated (or desensitized). For example, in type 2 diabetes, prolonged high insulin levels can lead to insulin receptor downregulation, contributing to insulin resistance.
Upregulation: Hormone receptors can also be upregulated, where the number of receptors increases to make the target cells more sensitive to the hormone. For instance, in hypothyroidism, the body may increase the number of TSH receptors to enhance the response to limited thyroid hormones.

The key takeaway is that hormone function is a complex interplay between hormone levels and their receptors.

And all of these elements are crucial for understanding hormones during perimenopause and menopause.

Now that you understand how hormones work (See? That wasn’t so hard), we’ll discuss progesterone, estrogens, and testosterone in relation to perimenopause.

Progesterone and Perimenopause

Progesterone is produced after ovulation by the corpus luteum in the ovary. The corpus luteum releases progesterone to prepare the uterine lining for a potential pregnancy and to support early pregnancy if fertilization occurs.

Outside of reproduction, progesterone has a calming effect on mood, promotes relaxation, reduces anxiety, and can contribute to better sleep by enhancing the neurotransmitter GABA.

Progesterone inhibits the proliferation of the endometrium (the lining of the uterus) and counteracts the proliferative effects of estrogen, helping to regulate the menstrual cycle and maintain a balance in endometrial growth.¹⁶³

Progesterone is the first hormone to decline as we enter perimenopause, likely due to ovarian aging and/or irregular ovulation.¹⁶⁶

Trouble sleeping?

Anxiety?

Mood swings?

Heavy periods?

Cycles getting closer together?

Any or all of these symptoms could be due to low levels of progesterone.

Understanding this hormonal change is vital for managing perimenopausal symptoms effectively.

Estrogen and Perimenopause

First off, estrogen is not the single hormone we think it is.

Estrogen is a collective term that refers to a group of related hormones called estrone (E1), estradiol (E2), and estriol (E3). These hormones are all types of estrogens, each with different bodily roles and functions.

Estrone is primarily produced in the ovaries, as well as in fat tissue. It is considered a weaker form of estrogen and becomes more dominant after menopause when estradiol levels decline. Estrone is thought to have pro-inflammatory effects, especially when present at higher levels relative to estradiol.

Estradiol is queen! She is the most potent form of estrogen and plays a crucial role in regulating the menstrual cycle, supporting pregnancy, and maintaining bone density, cardiovascular health, skin elasticity, mood, cognition, mental health, and more. Estradiol is anti-inflammatory, has antioxidant properties, and helps modulate immune cell activity in positive ways. Estradiol, in all cells/tissues, causes essential proliferation and necessary growth.¹⁶⁷

Estriol is the weakest of the three estrogens. While primarily known for its role during pregnancy, estriol plays a supportive role in women’s health outside of pregnancy, particularly in managing perimenopausal symptoms. Estriol has a selective binding pattern to estrogen receptors, which may provide beneficial effects on certain tissues (like vaginal and skin health) while exerting less influence on others (like the breast and uterus). My favorite application is for aesthetic purposes, as it’s been shown to improve skin elasticity, moisture, and help with anti-aging.

For simplicity's sake, we’ll call it estrogen. But estradiol is what we’re referring to.

As mentioned above, estradiol has many benefits (which only make sense if you consider how healthy you were in your 20s when estradiol was at its peak).

Overall, estrogen levels are declining in the perimenopause years. However, some women experience chaotic and unpredictable spikes in estrogen.

Here’s what you need to know about why estrogen levels become so unpredictable during perimenopause:

As a woman approaches menopause, the ovaries begin to function less consistently. Ovulation becomes less regular, leading to fluctuations in hormone production. Sometimes, the ovaries may not release an egg at all (anovulation), which can result in lower estrogen levels, while other times, ovulation might occur with an exaggerated release of estrogen.
The number of viable follicles in the ovaries decreases with age, reducing the overall production of estrogen. However, the remaining follicles may still occasionally produce a significant amount of estrogen, leading to spikes.
The communication between the hypothalamus, pituitary gland, and ovaries becomes less reliable during perimenopause. The pituitary gland continues to release follicle-stimulating hormone (FSH) to stimulate the ovaries, but the ovaries may not respond consistently, leading to fluctuating estrogen levels.
As the ovaries become less responsive, they may sometimes produce large amounts of estrogen in response to FSH, causing a spike, while at other times, they produce very little, leading to a drop.

Also, recall that low levels of progesterone only exacerbate these changes in estrogen, as the balance of estrogen and progesterone is critical to hormonal health.

Testosterone and Perimenopause

Testosterone is typically thought of as a male hormone, but women need it too, for:¹⁶⁸,¹⁷⁰

Bone health
Cognitive function
Energy levels
Muscle growth
Overall sense of well-being
Physical strength
Sexual desire and arousal
Mental health

In fact, when directly comparing the absolute amounts of testosterone to estrogen, women usually have more circulating testosterone (in ng/dL) than estrogen (in pg/mL)! And while we have about 10% the testosterone of men, it’s still super important for our physical, mental, and emotional health.¹⁷¹

If this resonates, there's more.

My newsletter and community are where I share clinical insight, evolving research, and what's helping women feel more like themselves again in midlife.

Testosterone levels can decline during perimenopause, although the changes are generally more gradual compared to declines in estrogen and progesterone and not experienced by all women. This is because androgens are made by the adrenal glands as well as by the ovaries.

Here's how testosterone is affected during perimenopause:

The ovaries produce testosterone along with estrogen and progesterone. As ovarian function diminishes during perimenopause, the production of all these hormones, including testosterone, decreases.
As you just learned, the adrenal glands also produce testosterone. However, aging and stress can affect overall adrenal function, contributing to a decline in testosterone levels.
As estrogen and progesterone levels fluctuate and decline, the relative balance of hormones is disrupted, which can impact the effects and bioavailability of testosterone.

If testosterone declines during perimenopause, this can contribute to symptoms such as decreased libido, reduced muscle mass, and changes in mood and energy levels.

However, the degree of testosterone decline and its impact can vary significantly among women.

Bottom line: Understanding the role testosterone, stress, and adrenal function play in perimenopause is essential to addressing symptoms at the root cause.

Is there a test for perimenopause? (Spoiler alert: there is no perfect test)

Unfortunately, there’s not a perfect test for perimenopause, which is why it is critical to know the signs of symptoms.

However, there are tests we can and should use to measure hormone levels and rule out other potential causal factors of symptoms, like hypothyroidism.

The following is a list of some of the tests I use to clinically assess perimenopause and rule out other possible conditions in my practice:

Follicle-Stimulating Hormone (FSH): Elevated FSH can indicate the onset of menopause as the ovaries produce less estrogen, but the levels typically don’t go up until you’re in full-blown menopause. High FSH can be an indication of premature ovarian failure in women under 40 who experience amenorrhea (lack of a period) and symptoms of low estrogen.
Estradiol: I think this is worth checking, but serum estradiol levels don’t always give us a reliable or definitive way of diagnosing perimenopause. This is because, as you’ve learned, estradiol levels can fluctuate significantly.
Progesterone: As you’ve also learned, low progesterone levels are common in perimenopause. This should be drawn during the second half or luteal phase; if not, it’s inaccurate.
Anti-Müllerian Hormone (AMH): This test can provide information about a woman's remaining egg supply (ovarian reserve). It is typically used in a fertility evaluation but can also provide information about a woman's reproductive aging. A very low AMH level can suggest that a woman is approaching menopause, but it cannot precisely predict when it will occur.
Thyroid Function Tests: Since thyroid disorders can mimic perimenopausal symptoms, checking thyroid function (TSH, T3, and T4 levels) is essential to rule out thyroid issues. Learn more in: A Functional Medicine Approach To Hashimoto's and Hypothyroidism.
Hemoglobin A1C (HbA1C) and Fasting Insulin: Hemoglobin A1c (HbA1c) is a blood test that measures the average blood glucose levels over the past 2 to 3 months. Specifically, it reflects the percentage of hemoglobin, a protein in red blood cells that carries oxygen, that is glycated (coated with glucose). A high HbA1C may indicate pre-diabetes or diabetes, and is also associated with an also increased risk of Alzheimer’s disease and cancer.
Complete Blood Count (CBC) and Metabolic Panel (CMP): These tests help rule out other conditions that might cause similar symptoms, such as anemia or metabolic disorders.
Nutritional Markers: vitamin and nutritional deficiencies are common and may mimic or exacerbate perimenopausal symptoms such as fatigue, mood swings, and cognitive changes. This includes Vitamin D, B12, Folate, Zinc, Iron, Magnesium, omega-3 fatty acid, and others.
hsCRP: Checking hsCRP can be a valuable tool for assessing inflammation and cardiovascular risk. It can provide insights into overall health and guide lifestyle and treatment choices aimed at reducing inflammation and its associated risks. However, because hsCRP is a nonspecific marker, elevated levels should be interpreted in context with other clinical findings and health assessments.
DUTCH Cycle Map: This dried urine test measures nine estrogen and progesterone levels throughout the cycle to track the follicular, ovulatory, and luteal phases. I find it helpful for determining hormone levels and tracking differences in the cycle phases. The downside is that it takes effort, time, and investment, so it’s not always a test we decide to run.

Since there is not one perfect test, your doctor or healthcare practitioner may not order all of these tests. Symptom tracking, cycle tracking, and age offer the best insights for diagnosing perimenopause.

They may not even offer them or recognize perimenopause as the cause of your symptoms.

Again, doctors weren’t taught much about this in school, so unless your provider has a special interest in women’s health and hormones, it’s easy to miss.

Regardless, it is essential to discuss symptoms and testing options with a healthcare provider to obtain a comprehensive assessment and appropriate diagnosis.

What are the treatment options for perimenopause?

This article was all about discussing the basics of perimenopause including what it is, how it differs from menopause, the age of onset, signs and symptoms, how the hormone piece works, and testing options.

Now that you’re an expert on all of that, we’ll be moving into treatment options in Part 2.

I’m a big advocate of HRT, a healthy lifestyle, and specific supplements that support hormone and adrenal health.

I know HRT is controversial in some spaces, which is why I will explain my recommendations fully in the next article, including a detailed overview of the science behind the risks and benefits of oral versus topical applications.

In the meantime, if you’d like help navigating the ups and downs of perimenopause from an integrative functional medicine perspective (and women who get it), we’d love to get to know you better.

Click here to learn more about our approach to functional medicine and how to become a patient.

Ready to get started right now? We have limited openings for new patients residing in California, Colorado, Illinois, Michigan, and Texas (where I am licensed).

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If you are not in one of the states we serve but want to keep in touch, subscribe to our Monthly Newsletter and follow us on social media @drchrstinemaren.

Finally, join us for Part 2 in our Perimenopause series, where we’ll discuss integrative treatment options to help you navigate this phase of life with energy, strength, and confidence.

What is perimenopause, and when does it start?

If this resonates, there's more.

What Is Perimenopause? Age Of Onset & How It Differs From Menopause

What Influences The Onset Of Perimenopause/ Menopause?

A Note About Toxin Exposure and Menopause

What are the signs and symptoms of perimenopause?

How do estrogen, progesterone and testosterone change in perimenopause?

Progesterone and Perimenopause

Estrogen and Perimenopause

Testosterone and Perimenopause

If this resonates, there's more.

Is there a test for perimenopause? (Spoiler alert: there is no perfect test)

What are the treatment options for perimenopause?

Sources