Perimenopause — What’s Actually Happening and Why It Feels So Confusing

Why This Is the Spotlight Article for the New Year ✨

I chose to lead the new year with this topic deliberately.

Perimenopause is not a niche issue. It is a universal life transition, one that affects health, work, relationships, and long-term disease risk—yet it remains one of the most misunderstood phases of women’s lives. Too often, women enter it without context, without language, and without reliable guidance.

A new year is the right moment to reset expectations.

Before we talk about treatments, prescriptions, or protocols, we need a shared understanding of what is actually happening in the body. Without that foundation, everything else—medical care, self-advocacy, and decision-making—becomes harder than it needs to be.

This article sets the tone for the year ahead:

We will start with physiology, not hype.
We will prioritize education over fear.
We will focus on long-term health, not quick fixes.

If we get the definitions right, we get the care right. That’s why this conversation comes first—and why it matters now.

One of the most common things I hear from women in their late 30s and 40s is some version of this:

“I don’t feel like myself anymore — but every test keeps coming back ‘normal.’”

If that sounds familiar, you’re not alone. And you’re not imagining it.

This month, I want to talk about perimenopause — what it is, when it really begins, and why so many women feel dismissed or misled during this phase of life.

Why Definitions Matter and Why We’re Talking About Them Now

It’s worth noting that clarifying definitions was the focus of the very first plenary lecture at the 2025 Menopause Society Annual Meeting in October 2025. The opening session was devoted entirely to defining perimenopause, reviewing its epidemiology, and explaining the hormonal physiology of the transition.

That choice was intentional.

When national experts feel the need to start a major scientific meeting by aligning on basic terminology, it tells us something important: even within medicine, these terms have been inconsistently used and poorly understood.

If clinicians and researchers need to pause and recalibrate language, then we have an obligation to disseminate that clarity more broadly—so patients, providers, and the public are all speaking the same language.

Shared definitions matter. They shape expectations, guide care, and protect patients from confusion and misinformation. My goal in including this here is simple: when we understand the terms, we understand the process—and that understanding is the foundation of good care.

First: What Is Perimenopause?

Perimenopause is the menopausal transition — the long, often messy stretch of time before the final menstrual period and continuing through the first year after it.

It does not start when your periods stop.
It does not start with low estrogen.
And it does not look the same for every woman.

Perimenopause typically begins in the late 30s to early 40s, years before menopause itself. For many women, symptoms begin well before anyone labels what’s happening.

Menopause, by contrast, is defined very narrowly:
12 consecutive months without a menstrual period, confirmed only in retrospect.

Everything before that? That’s perimenopause.

The Biology Behind the Chaos

Here’s the part that surprises most women:
Perimenopause is not a smooth, gradual hormone decline.

It’s more like white-water rafting.

What’s happening inside the ovaries:

You’re born with all the follicles you’ll ever have.
That number steadily declines across life.
By perimenopause, the remaining follicles are fewer — and less predictable.

As a result:

FSH rises, largely because inhibin-B (a key ovarian signal) is falling.
Estradiol does not gently taper — instead, it swings wildly.
Some cycles produce estradiol levels higher than anything seen earlier in life.
Other cycles crash toward postmenopausal levels.

These dramatic swings — not just “low estrogen” — explain:

Hot flashes and night sweats
Sleep disruption
Mood changes
Anxiety
Brain fog
Headaches
Breast tenderness
Irregular or heavy bleeding

If you’ve been told, “Your estrogen looks normal, so this can’t be perimenopause,” that reflects a misunderstanding of how this transition actually works.

Why Blood Tests Are Often Unhelpful

One of the most important take-home points from this lecture is this:

There is no single lab test that can diagnose or rule out perimenopause.

Here’s why:

FSH fluctuates widely and can’t be “normalized” with estrogen alone.
Estradiol can be very high one week and very low the next.
AMH declines as menopause approaches, but variability between women limits its routine use.
A single hormone snapshot rarely reflects the full picture.

Perimenopause is diagnosed clinically, using:

Age
Menstrual pattern changes (cycle length variability, skipped cycles)
Symptoms (especially vasomotor symptoms, sleep, mood, cognition)

Labs have a role in fertility counseling or ruling out other conditions — but they are not the primary diagnostic tool.

Bleeding Changes: What’s Normal — and What Isn’t

Irregular bleeding is common during perimenopause. That includes:

Shorter or longer cycles
Heavier flow
Skipped periods followed by heavier bleeding

However, heavy or abnormal bleeding still deserves evaluation. Perimenopause does not exempt anyone from appropriate assessment for structural or non-structural causes.

Anemia, fatigue, and quality-of-life impairment are real consequences — and they’re treatable.

Perimenopause Is Also a Metabolic Transition

Long before menopause is “official,” important changes are already underway:

Bone resorption accelerates
LDL cholesterol rises
Metabolic-syndrome parameters worsen

This is why I often describe perimenopause as a portal — a window of opportunity to:

Protect bone health
Address cardiovascular risk
Support metabolic and cognitive health
Normalize what’s happening instead of reacting late

Not All Women Experience This the Same Way

Large studies show meaningful differences:

Black women may experience vasomotor symptoms for up to 10 years
Non-Hispanic White women average around 6 years
Hispanic and Chinese women closer to 5 years

Obesity and smoking history are associated with more frequent and severe symptoms.

Women without periods — after hysterectomy or ablation — often use hot flashes and night sweats as the best clinical marker of transition.

Common Myths I Want to Retire

❌ “You’re too young for perimenopause.”
❌ “Your labs are normal, so this isn’t hormonal.”
❌ “Estrogen should fix your FSH.”
❌ “We’ll talk about this when your periods stop.”

Perimenopause is universal, highly variable, and often misunderstood — even in medical settings.

What I Want You to Take Away

Perimenopause begins years before the final period
Diagnosis is clinical, not lab-based
Estradiol swings are extreme — symptoms often reflect peaks, not just deficiency
Race, body composition, and smoking history influence symptom duration
Early counseling and preventive care matter

Most importantly: what you’re experiencing is real, explainable, and deserving of thoughtful care.

In upcoming newsletters, I’ll walk through symptom-management options and how we individualize treatment during this transition. But understanding what’s happening is the first step — and one many women never receive.

You deserve better than confusion.

— April