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Perimenopause in Your Early 40s: Recognising the Shift

Perimenopause commonly begins in the early 40s. Learn to recognise the signs, understand what's happening hormonally, and find practical ways to feel more in control.

4 min readFebruary 28, 2026

The Most Common Time for Things to Start Shifting

For many women, the early 40s is when perimenopause begins to make itself known. Hormonal fluctuations become more pronounced at this stage, even if full menopause is still a decade away. Estrogen and progesterone levels start to become less predictable, and the body begins adapting to these new rhythms. Understanding this transition is the first step toward managing it well.

What Symptoms Tend to Look Like in Your Early 40s

Cycle irregularity is one of the earliest and most consistent signs. Periods may start arriving closer together, or gaps between them may lengthen. PMS can intensify even if you've never had much trouble with it before. Sleep often becomes lighter and more disrupted, and many women notice a change in energy levels, particularly in the second half of the cycle. Brain fog, which shows up as forgetfulness or difficulty concentrating, is another common early feature.

The Hormonal Picture Behind the Changes

In your early 40s, the ovaries begin producing fewer follicles each month, and progesterone often drops first. This can create a relative estrogen dominance for a period of time, which contributes to heavier periods, breast tenderness, and mood changes. Eventually estrogen levels become more erratic too, rising and falling unpredictably. These fluctuations, rather than a steady decline, are what drive many of the more disruptive symptoms in this early phase.

Building Habits That Will Carry You Through

What you do now sets the tone for the years ahead. Prioritising sleep is foundational. Protein intake becomes more important as muscle mass is easier to lose in this hormonal environment. Strength training, even twice a week, helps protect both muscle and bone. Managing stress, whether through walks, time alone, or whatever genuinely works for you, matters more than ever because cortisol amplifies hormonal symptoms.

Keeping a Record of Your Experience

Early perimenopause can be hard to pin down because symptoms come and go unpredictably. Tracking your symptoms consistently over time reveals patterns that aren't obvious in the moment. PeriPlan lets you log what you're experiencing and track how symptoms shift across weeks and months, which can be genuinely useful when speaking with a doctor or deciding what changes to try.

Related reading

ArticlesPerimenopause in Your Late 30s: What to Know and Expect
ArticlesPerimenopause in Your Mid 40s: Managing a More Intense Phase
GuidesPerimenopause and Work: How to Navigate Brain Fog, Hot Flashes, and Fatigue on the Job
Medical disclaimerThis content is for informational purposes only and does not constitute medical advice, diagnosis, or treatment. Always consult a qualified healthcare provider with questions about a medical condition. PeriPlan is not a substitute for professional medical advice. If you are experiencing severe or concerning symptoms, please contact your doctor or emergency services immediately.

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