Perimenopause: Signs, Symptoms, and What to Do

Introduction

Perimenopause is the transitional phase leading up to menopause — and for many women, it arrives years before they expect it, with symptoms they don't recognise.

The word "menopause" gets most of the attention, but perimenopause — which can last 4 to 10 years — is where most of the symptoms actually occur. Irregular periods, hot flushes, sleep disruption, mood changes, brain fog, and changes in sexual function can all begin while you're still having regular (if unpredictable) periods.

Understanding what perimenopause is, what to expect, and what options are available can make an enormous difference in how you navigate this life stage.

What Is Perimenopause?

Perimenopause (literally "around menopause") is the period of hormonal transition that precedes menopause. It begins when the ovaries start to produce less oestrogen and progesterone — hormones that have regulated your menstrual cycle, fertility, sleep, mood, and much more.

Menopause is defined as 12 consecutive months without a menstrual period. Perimenopause ends when that threshold is reached.

Post-menopause is everything after.

The hormonal changes of perimenopause are not linear. Oestrogen levels fluctuate irregularly — sometimes surging higher than normal, sometimes dropping — before eventually declining to consistently low levels. This hormonal turbulence drives many of the symptoms.

When Does Perimenopause Start?

Most women enter perimenopause in their mid-to-late 40s, though it can begin as early as the late 30s. The average age of menopause in Singapore and other Asian populations is approximately 49–51 years, with perimenopause typically beginning 4–6 years earlier.

Factors that influence timing:

• Genetics: The age your mother and sisters entered menopause is the strongest predictor of your own timing
• Smoking: Associated with earlier menopause (by 1–2 years)
• Chemotherapy or radiation: Can trigger premature ovarian insufficiency
• Surgical menopause: Bilateral oophorectomy (removal of both ovaries) causes immediate surgical menopause, bypassing perimenopause

Premature ovarian insufficiency (POI) — previously called premature menopause — refers to ovarian failure before age 40, affecting approximately 1% of women. This warrants prompt specialist evaluation.

Key Signs and Symptoms of Perimenopause

1. Irregular Periods

The most classic early sign. Cycles may become longer or shorter, skipped, or change in flow intensity (heavier or lighter). This reflects the increasing irregularity of ovulation as ovarian reserve declines.

Important: Not all irregular bleeding is perimenopause. Heavy bleeding, spotting between periods, or bleeding after sex should always be evaluated by a doctor to rule out other causes.

2. Hot Flushes and Night Sweats

Vasomotor symptoms — hot flushes during the day and night sweats during sleep — are experienced by approximately 75% of women during the menopause transition. They result from oestrogen withdrawal affecting the hypothalamus's temperature regulation.

Hot flushes are characterised by a sudden sensation of heat spreading across the chest, neck, and face, often accompanied by flushing, sweating, and sometimes palpitations. Duration is typically 1–5 minutes; frequency varies widely.

3. Sleep Disturbances

Sleep problems during perimenopause are multi-factorial: night sweats disrupt sleep directly, falling oestrogen and progesterone alter sleep architecture, and mood changes contribute to insomnia. Poor sleep can then worsen every other symptom.

4. Mood Changes

Anxiety, irritability, sadness, and emotional volatility are common during perimenopause, even in women with no prior history of mental health difficulties. Oestrogen has significant effects on serotonin, dopamine, and GABA pathways — the key neurotransmitter systems regulating mood.

Research shows the menopause transition is a period of elevated risk for clinically significant depression, with a 2-fold increase compared to premenopausal status (PMID: 16529173).

5. Cognitive Changes ("Brain Fog")

Many women in perimenopause report difficulty with word retrieval, concentration, and short-term memory. These changes are generally temporary and not indicative of dementia, but they can be distressing.

Oestrogen plays a role in cerebral blood flow, neuronal signalling, and the metabolism of acetylcholine — a neurotransmitter important for memory.

6. Vaginal and Urinary Changes (Genitourinary Syndrome of Menopause, GSM)

Declining oestrogen leads to thinning and drying of vaginal and urethral tissues (vaginal atrophy). This causes:

• Vaginal dryness, irritation, and discomfort during sex
• Increased urinary urgency and frequency
• Increased susceptibility to urinary tract infections

Unlike hot flushes, which often improve over time, GSM tends to worsen if untreated.

7. Changes in Libido

Sexual desire may decrease in perimenopause due to falling oestrogen and testosterone levels, as well as vaginal discomfort making sex less enjoyable.

8. Joint Pain and Muscle Aches

A less-discussed symptom: oestrogen has anti-inflammatory properties, and its decline can manifest as joint stiffness and musculoskeletal pain.

9. Skin and Hair Changes

Oestrogen supports collagen production and skin hydration. Declining levels lead to drier, thinner skin and increased wrinkling. Hair may become finer or begin thinning.

10. Changes in Body Composition

Many women notice increased abdominal fat during perimenopause, even without changes in diet or exercise. This reflects both hormonal effects on fat distribution and age-related metabolic changes.

How Is Perimenopause Diagnosed?

Perimenopause is primarily a clinical diagnosis based on age, symptoms, and menstrual history.

Blood tests can be supportive but are not always definitive, as hormone levels fluctuate significantly during perimenopause:

• FSH (follicle-stimulating hormone): Elevated FSH (typically > 25–40 IU/L) suggests reduced ovarian reserve, but levels vary day to day
• Oestradiol: Low and variable during perimenopause
• AMH (anti-Müllerian hormone): A marker of ovarian reserve, more stable than FSH

In women over 45 with classic symptoms, blood tests are often not necessary for diagnosis.

What Can You Do? Treatment and Management Options

Lifestyle Approaches

• Regular exercise: Reduces vasomotor symptoms, improves sleep, mood, and bone density
• Healthy diet: Mediterranean-style eating supports cardiovascular and metabolic health during this vulnerable transition
• Limit alcohol and smoking: Both worsen vasomotor symptoms and accelerate bone loss
• Stress management: Mindfulness, yoga, and cognitive behavioural therapy (CBT) have evidence for symptom reduction

Hormone Replacement Therapy (HRT)

HRT — replacing oestrogen (and progesterone, if the uterus is intact) — is the most effective treatment for vasomotor symptoms, sleep disruption, GSM, and mood changes associated with perimenopause.

Modern evidence supports the safety and efficacy of HRT for most healthy women under 60 or within 10 years of menopause. The 2023 British Menopause Society guidelines and the International Menopause Society strongly recommend that HRT be offered to symptomatic women without contraindications.

Non-Hormonal Options

For women who prefer not to use HRT or have contraindications:

• SSRIs/SNRIs (e.g., paroxetine, venlafaxine): Effective for hot flushes and mood symptoms
• Gabapentin: Shown to reduce vasomotor symptoms
• Oxybutynin: May reduce hot flush frequency
• Vaginal oestrogen: Low-dose local oestrogen for GSM is considered safe even in women who cannot use systemic HRT

Emerging Options

Fezolinetant — a neurokinin B receptor antagonist — is a novel non-hormonal treatment specifically targeting the neurological pathway driving hot flushes, recently approved in several markets.

When to See a Doctor

See a doctor if:

• You have heavy or irregular bleeding that is new, very heavy, or accompanied by pain
• Symptoms are significantly affecting your quality of life, sleep, or mental health
• You are under 45 with possible perimenopause symptoms (earlier evaluation is important)
• You are interested in understanding your treatment options

The Bottom Line

Perimenopause is a significant life transition — and one that women deserve honest, evidence-based information about. Symptoms are real, varied, and often start earlier than women expect.

The good news: effective treatments exist. You don't have to manage this alone or just "push through."

Think you might be in perimenopause? Speak with a Zoey doctor for a personalised, evidence-based assessment of your symptoms and options.