Perimenopause: what it is, what changes in your body and how to recognize it
by BelénShare
Almost everyone has heard about menopause since they were young. Perimenopause, the transition that precedes it and can last several years, is talked about far less. Many women don't understand what's happening until their cycles change, sleep stops feeling the same, or symptoms appear that are hard to connect to one another.
Understanding what changes first in the body makes it easier to interpret any specific symptom later on. Before talking about hot flashes, mood changes or sleep disruption, it helps to know what happens in the system that gives rise to all of them: the communication between the brain and the ovaries.
What perimenopause actually is
Perimenopause, menopause and the climacteric are often used as synonyms, but they describe different moments of the same transition. Telling them apart helps clarify where each woman stands.
| Term | What it means |
|---|---|
| Perimenopause | The transition stage toward menopause. Cycles start to change and ovarian function declines progressively (Harlow et al., 2012). |
| Menopause | It doesn't describe a period of time, but a specific point: it's confirmed retrospectively after twelve consecutive months without a period (Harlow et al., 2012). |
| Climacteric | A term that covers the whole transition, from the last reproductive years through the stage that follows menopause (Davis et al., 2023). |
This article focuses on perimenopause: the stage where most hormonal changes begin and, at the same time, one of the least understood by the general public.
How the brain and the ovaries communicate
During the reproductive years, the brain and the ovaries maintain constant communication. The hypothalamus and the pituitary gland send hormonal signals, mainly FSH and LH, which stimulate ovarian activity. The ovary responds by producing estrogen and, after ovulation, progesterone (Santoro et al., 2021).
| Organ | Its role in the cycle |
|---|---|
| Brain (hypothalamus and pituitary gland) | Sends FSH and LH signals that stimulate ovarian activity. |
| Ovaries | Produce estrogen and progesterone, and send that information back to the brain to adjust the next cycle. |
It is this balance that begins to shift during perimenopause.
What actually changes in that loop
Several processes take place at once during perimenopause. They start gradually and end up overlapping with one another (Santoro et al., 2021; Davis et al., 2023).
Ovulation becomes irregular. Not every cycle includes ovulation. When a cycle is anovulatory, the hormonal pattern that month changes, mainly because of lower progesterone production.
FSH starts to rise. As the ovary responds less efficiently, the feedback it sends to the brain decreases. The pituitary gland releases more and more FSH trying to stimulate new follicles.
Estrogen starts to fluctuate. There can be months with higher than usual levels and others with marked drops. That's why symptoms vary so much from one cycle to the next.
Progesterone falls earlier and faster. Since it's produced mainly after ovulation, frequent anovulatory cycles also reduce its production. This can disrupt sleep and increase vulnerability to anxiety.
The two phases of the transition and how to tell them apart
Although every woman experiences this stage differently, there is a widely used clinical framework to describe how the transition to menopause progresses. It's called STRAW+10, and it divides perimenopause into two phases based on changes in the menstrual cycle (Harlow et al., 2012).
| Phase | What it means |
|---|---|
| Early transition | The cycle is still recognizable, but it varies persistently: a difference of seven days or more compared with its usual length. |
| Late transition | Episodes of sixty days or more without a period appear. Hot flashes and night sweats also tend to increase more often at this stage. |
The stage of the transition is defined by the menstrual cycle pattern, not by the number or intensity of symptoms. Two women can be in the same phase and experience completely different symptoms.
What the clinical criteria say
Perimenopause usually isn't confirmed with a single test or a single hormone panel. In clinical practice, the diagnosis relies mainly on menstrual history, symptoms and how they evolve over time (Harlow et al., 2012).
One of the best-studied aspects is vasomotor symptoms, especially hot flashes and night sweats. When they appear early in the transition, they're more likely to persist for longer (Avis et al., 2015).
For that reason, a single hormone test usually provides little information during perimenopause. Hormone levels naturally fluctuate from one cycle to the next (Santoro et al., 2021; Huibregtse et al., 2026).
Can I still get pregnant?
Yes. It's one of the most common questions during perimenopause.
Ovulation stops happening in every cycle, but it doesn't disappear completely. As long as occasional ovulations continue, pregnancy is possible, even if periods are irregular (Santoro et al., 2021).
Fertility declines progressively. Ovulations become less frequent and ovarian reserve decreases over time. That doesn't mean pregnancy stops being possible.
Ideas worth clarifying
"There's no fixed age or order"
One of the biggest sources of confusion during perimenopause is comparing yourself to other women. Some start with changes in their menstrual cycle. Others first seek advice because of hot flashes, trouble sleeping or mood changes. All of them can be going through the same transition.
The transition usually begins between 45 and 47 years old, although there's considerable variability (Santoro et al., 2021). Nor does every woman experience every symptom.
"A hormone test doesn't replace tracking your cycle"
A single hormone value captures only one moment in time. What defines perimenopause is precisely its variability. That's why how the cycle and symptoms evolve is usually more useful than a single test result (Santoro et al., 2021; Huibregtse et al., 2026).
How it can show up in the body
Perimenopause doesn't affect just one organ. Hormonal changes can show up across different systems, although not every woman has the same symptoms or the same intensity.
| System | What you may notice |
|---|---|
| Nervous system | Hot flashes, night sweats, trouble falling or staying asleep, mood changes and brain fog. |
| Cardiovascular system | Higher LDL cholesterol, lower HDL, and blood vessels with less capacity to dilate. |
| Bone and muscle | Faster bone mass loss and more difficulty maintaining muscle mass and strength. |
| Genitourinary system | Vaginal dryness and irritation, discomfort during sex and greater urinary urgency. |
| Skin and hair | Lower collagen production, loss of firmness, more dryness and lower hair density. |
| Metabolism | Fat redistribution toward the abdomen and more difficulty maintaining weight. |
Recognizing the mechanism behind each symptom helps distinguish what's part of the hormonal transition from what might have another cause and deserves a separate evaluation.
When it's worth consulting before your next appointment
As soon as you start noticing changes like the ones described in this article, it's worth talking to your gynecologist, even if the symptoms seem mild. It's common to normalize discomforts that actually have a treatment.
- Bleeding is very heavy, lasts longer than usual, or occurs between periods. Some bleeding changes require evaluation to rule out other causes (NICE, 2024; Davis et al., 2023).
- Hot flashes or insomnia significantly affect your rest or quality of life. Treatment options exist that can improve these symptoms (Davis et al., 2023).
- You have persistent pelvic pain or a new symptom that doesn't fit your usual pattern. Not every symptom at this stage is due to the hormonal transition (Davis et al., 2023).
- Mood changes are intense, or symptoms of anxiety or depression appear that interfere with your daily life. Mental health is also part of health during perimenopause (Davis et al., 2023).
Most of the changes that appear during perimenopause are part of a physiological transition. Consulting a professional when something falls outside what's expected helps you get the most appropriate treatment and rule out other possible causes.
Who is this information for?
For any woman who wants to understand what's happening in her body during this transition and how to recognize it in herself. This article doesn't replace a medical consultation or a diagnosis: its goal is to offer an evidence-based framework that supports a more informed conversation with your gynecologist.
Frequently asked questions
Does this article replace a medical consultation?
No. It's information to help you understand what's happening in your body, not a diagnosis. Only a healthcare professional can confirm that.
Why don't my symptoms match exactly what's described here?
Variability between women is high. Not everyone experiences the same symptoms, in the same order, or with the same intensity.
Do I need a hormone test to confirm I'm at this stage?
It can be part of a professional's evaluation, but a single value captures only one moment of a system that is defined, precisely, by constant change.
How long does this transition last?
It varies between women. As a reference, vasomotor symptoms last an average of 7.4 years according to the SWAN study, although some women experience them for much less time and others for more than a decade (Avis et al., 2015).
If I still get my period, can I be in perimenopause?
Yes. Most women go through perimenopause while still menstruating. It begins when persistent changes appear in cycle length, not when periods stop altogether (Harlow et al., 2012).
Quick glossary
- Perimenopause
- The transition stage toward menopause, during which the cycle and hormones change progressively.
- Menopause
- A point in time confirmed retrospectively after twelve consecutive months without a period.
- Climacteric
- A term that covers the whole transition, from the last reproductive years through the period after menopause.
- FSH (follicle-stimulating hormone)
- A hormone released by the pituitary gland to stimulate ovarian activity; it rises as the ovary responds less efficiently.
- Anovulatory cycle
- A menstrual cycle in which ovulation doesn't occur, increasingly common during perimenopause.
- STRAW+10
- The reference clinical framework that describes the phases of the reproductive transition based on changes in the menstrual cycle.
In summary
Perimenopause isn't defined by a single symptom, a specific age, or a hormone test. It's recognized by observing how the cycle, ovulation and hormones change over time, and that change can show up in very different ways from one woman to another. Understanding this map doesn't remove the symptoms, but it does change what you can do about them: talking to your gynecologist as soon as they appear is the first step toward living this stage in a much better way.
The SKINVITY team
Scientific references
The following references correspond to the general scientific evidence on the physiology of the perimenopausal transition cited in this article, not to an efficacy study of a SKINVITY device.
- Harlow SD, Gass M, Hall JE, et al.; STRAW+10 Collaborative Group. Executive summary of the Stages of Reproductive Aging Workshop + 10. J Clin Endocrinol Metab. 2012;97(4):1159-1168.
- Santoro N, Roeca C, Peters BA, Neal-Perry G. The Menopause Transition: Signs, Symptoms, and Management Options. J Clin Endocrinol Metab. 2021;106(1):1-15.
- Davis SR, Pinkerton J, Santoro N, Simoncini T. Menopause: Biology, consequences, supportive care, and therapeutic options. Cell. 2023;186(19):4038-4058.
- Huibregtse ME, Taylor L, Prochaska T, et al. Considerations and practical recommendations for identifying perimenopause in longitudinal research. Psychoneuroendocrinology. 2026;186:107748.
- Avis NE, Crawford SL, Greendale G, et al.; Study of Women's Health Across the Nation. Duration of menopausal vasomotor symptoms over the menopause transition. JAMA Intern Med. 2015;175(4):531-539.
- Thornton MJ. Estrogens and aging skin. Dermatoendocrinology. 2013;5(2):264-270.
- National Institute for Health and Care Excellence (NICE). Menopause: identification and management. NICE Guideline NG23. Updated 2024.