Perimenopause is the “transition time” before menopause when your ovaries begin to shift how (and when) they produce hormones—especially estrogen and progesterone. For many women, the tricky part is that perimenopause is most often diagnosed based on symptoms and patterns, not a single blood test.

If you’ve been thinking, “Something feels off, but my labs look normal,” you’re not alone. Hormones can fluctuate day to day (even hour to hour), so a one-time lab draw may not reflect what’s happening across your whole cycle.

Below is a practical, menopause-informed way to recognize perimenopause—and what you can do next.

What Counts As Perimenopause?

Perimenopause is the stretch of time leading up to menopause. Menopause is defined as 12 consecutive months without a period. Perimenopause is everything that happens before that “one-year mark,” when cycles and symptoms start changing.

It often begins in your 40s, but it can start in the mid-to-late 30s for some women.

Common Signs You Might Be In Perimenopause

Perimenopause is usually identified by a mix of age + cycle changes + symptoms. Symptoms can be subtle at first and then become more noticeable over time.

Common symptoms include:

• Irregular periods (shorter cycles, longer cycles, skipped cycles)
• Heavier or different bleeding patterns than your usual
• Sleep issues (trouble falling asleep, waking at 2–4 a.m., lighter sleep)
• Hot flashes or night sweats
• Mood changes, irritability, or more anxiety than usual
• Breast tenderness
• Weight changes (especially around the midsection)
• Increased stress sensitivity (less resilience, more overwhelm, easier burnout)

A key clue is pattern: symptoms may cluster in certain parts of your cycle, appear suddenly when they never used to, or ramp up during stressful seasons of life.

Why A Single Blood Test Often Doesn’t “Diagnose” Perimenopause

This is one of the biggest frustrations for patients: you can feel very different, yet your lab report says everything is “normal.”

Here’s why that happens:

• Hormone levels fluctuate daily in perimenopause.
• Even within a single cycle, estrogen and progesterone rise and fall in predictable phases—except those patterns can become less predictable during the transition.
• If you test on a day when your hormones happen to be in a “normal-looking” range, your results may not match your real-life experience.

That’s why a menopause-informed clinician typically does not rely on one estrogen or FSH number alone to determine whether you’re in perimenopause.

What A Menopause-Informed Clinician Looks At Instead

A menopause-informed clinician uses your symptoms, cycle patterns, and age to determine where you likely are in the transition—then uses labs thoughtfully to rule out other common “look-alikes.”

They may ask questions like:

• How has your cycle changed over the last 6–24 months?
• Are you noticing sleep disruption, mood changes, or hot flashes?
• Do symptoms worsen before your period (or when your period is late)?
• Have you developed new headaches, heavier bleeding, or worsening PMS?
• Are stress, caffeine, alcohol, or late-night eating affecting symptoms more than they used to?

Labs can still be useful—but often in a different way. For example, it’s common to evaluate factors that can mimic or worsen perimenopause symptoms, such as:

• Thyroid function (fatigue, brain fog, weight changes, anxiety can overlap)
• Blood sugar and insulin patterns (energy crashes, weight gain, sleep disruption)
• Nutrient status (iron, B12, vitamin D—especially if bleeding is heavier)
• In some cases, markers of inflammation or cardiometabolic risk as your physiology shifts

When To Get Checked Right Away

Perimenopause can be normal, but some symptoms deserve prompt evaluation. Contact a clinician if you have:

• Bleeding that is extremely heavy, prolonged, or includes large clots
• Bleeding between periods or after sex
• New or worsening pelvic pain
• Dizziness, shortness of breath, or signs of anemia
• Hot flashes/night sweats that significantly disrupt sleep and daily function
• New mood symptoms that feel intense or unsafe

These don’t automatically mean something serious is happening, but they do mean it’s worth getting support sooner rather than later.

Science Section (Selected References)

• The Menopause Society (NAMS): Nonhormone Therapy Position Statement (2023)
• Yoga For Menopausal Symptoms (Meta-Analysis)
• Behavioral Weight Loss And Hot Flashes (Clinical Trial)
• CBT-I For Menopause-Related Insomnia (Randomized Trial)

How Peace And Calm Health Functional Medicine Can Help

At Peace and Calm Health Functional Medicine in Lakewood, CO, the goal is to help you understand what’s driving your symptoms and create a plan that supports your whole system—especially thyroid health, insulin/blood sugar patterns, nutrition, sleep, and stress physiology.

If you’re wondering whether you’re in perimenopause, a helpful next step is a structured visit that looks at:

• Your symptom timeline and cycle changes
• Your stress load and sleep patterns
• Targeted labs to rule out common contributors (like thyroid or metabolic imbalance)
• A personalized plan built around realistic nutrition, lifestyle, and supportive strategies

To explore next steps, book a Clarity Call here:
https://www.drjenniferhorton.com/work-with-me

You can also learn more about wellness programs here:
https://www.drjenniferhorton.com/wellness-programs

Medically reviewed by Dr. Jennifer Horton, DO, ABFM, IFMCP

This content is for educational purposes and does not substitute personalized medical advice.