Perimenopause is the transition leading up to menopause. It can begin while periods are still regular and may cause changes in the menstrual cycle, sleep, temperature regulation, mood, concentration and intimate health. It often starts in the 40s and can last for several years, although every woman’s experience is different. Recognising the pattern can help you seek appropriate support and rule out other possible causes.
Key points
- Perimenopause begins with the first changes associated with declining ovarian function and ends 12 months after the final menstrual period.
- Early signs may include irregular or heavier periods, hot flushes, night sweats, sleep disruption and mood changes.
- A single hormone test cannot reliably confirm or exclude perimenopause because hormone levels fluctuate.
- Pregnancy remains possible until menopause has been confirmed.
- New, disruptive or unusual symptoms deserve medical attention; not every change in midlife is caused by hormones.
What is perimenopause?
Perimenopause means “around menopause”. It describes the years during which ovarian activity becomes less predictable before periods stop permanently. Menopause itself is confirmed retrospectively after 12 consecutive months without a period, provided there is no other explanation.
The term “premenopause” is sometimes used informally for the years before the final period. Perimenopause is more precise because it includes the whole transition, from the first menstrual or symptom changes through to one year after the last period.
French national health guidance notes that symptoms commonly appear around age 47 and that the transition often begins two to four years before menopause. These are averages, not deadlines: timing, duration and intensity differ considerably.
At what age does perimenopause start?
Perimenopause most often begins during the 40s, but it can start earlier or later. There is no single age at which every woman should expect symptoms.
Medical advice is especially important when periods become very irregular or stop before age 45. Before age 40, primary ovarian insufficiency should be considered. This requires specific assessment because of its possible implications for fertility, bone health and cardiovascular health.
What are the early signs of perimenopause?
The clearest early sign is often an unfamiliar change in the menstrual cycle. However, the transition can affect much more than periods.
Changes to periods
Cycles may become shorter, longer or less predictable. Bleeding can become heavier, lighter or last longer, and some periods may be missed. These changes can occur in perimenopause, but very heavy bleeding, bleeding between periods, bleeding after sex or any pattern that feels unusual should be assessed.
Hot flushes and night sweats
A sudden wave of heat may move across the chest, neck and face, sometimes followed by sweating, palpitations or chills. At night, these episodes may interrupt sleep and contribute to daytime fatigue.
Poor or disrupted sleep
Difficulty falling asleep, waking repeatedly or waking too early may occur with or without night sweats. Anxiety, pain, urinary symptoms and everyday stress can also affect sleep, so the cause is often multifactorial.
Mood changes
Some women experience increased irritability, anxiety, emotional sensitivity or low mood. These symptoms should be taken seriously rather than dismissed as “just hormones”. Persistent distress, severe depression or thoughts of self-harm require prompt professional support.
Brain fog and concentration difficulties
Forgetfulness, difficulty finding words or feeling mentally slower are commonly reported. Poor sleep, stress, medication and other health conditions may contribute. Sudden, severe or progressive cognitive change requires medical assessment.
Physical changes
Fatigue, headaches, joint discomfort, drier skin and changes in body composition can occur. None is specific to perimenopause: thyroid disease, iron deficiency, metabolic conditions and medication effects can produce similar symptoms.
Sexual and intimate health
Vaginal dryness, discomfort during sex, lower desire and urinary symptoms may begin during the transition. They are common but should not be normalised as something women simply have to tolerate; effective options are available.
Why do symptoms vary so much?
Oestrogen and progesterone do not decline in a smooth, predictable line. Levels may change considerably between cycles and even within the same month. Two women of the same age may therefore have completely different experiences, while one woman may alternate between relatively calm and highly symptomatic phases.
Health history, mental wellbeing, sleep, stress, smoking, alcohol, physical activity, social context and medication can also influence symptoms.
How is perimenopause identified?
Assessment is primarily based on age, cycle changes, symptoms and medical context. There is no single test that can accurately determine whether someone is in perimenopause or predict exactly when their final period will occur.
Are hormone tests useful?
Not routinely. Follicle-stimulating hormone (FSH) and oestradiol can fluctuate widely. A “normal” result does not rule out perimenopause, while one elevated result may not confirm it.
Targeted testing can be useful when symptoms occur before age 45, primary ovarian insufficiency is suspected, periods stop for an unexplained reason, hormonal contraception complicates the picture or another condition needs to be excluded. Results must be interpreted alongside symptoms, cycle timing, medication and medical history.
What else can look like perimenopause?
Pregnancy, thyroid disorders, iron-deficiency anaemia, polycystic ovary syndrome, medication effects, high stress and gynaecological conditions can cause similar changes. The purpose of a consultation is not simply to “check hormones”, but to understand the complete pattern.
Can you still become pregnant?
Yes. Fertility decreases with age, but ovulation can still occur during perimenopause. Contraception may therefore remain necessary until a healthcare professional confirms it can be stopped. The timing depends on age, contraceptive method and individual circumstances.
What can help during perimenopause?
Treatment should reflect the symptoms that matter most, their impact, the need for contraception, medical history and personal preferences.
Track the pattern
For several weeks, record cycle dates and bleeding, hot flushes, sleep, mood, headaches, urinary or vaginal symptoms and their impact. A timeline is often more helpful than trying to remember everything during an appointment.
Support long-term health without blame
Regular movement, strength training, balanced nutrition, protected sleep, stopping smoking and limiting alcohol support cardiovascular, bone and metabolic health. These measures do not remove every symptom and should not replace medical treatment when it is needed.
Discuss treatment options
Depending on the individual, options may include hormonal contraception, menopausal hormone therapy, local treatment for vaginal symptoms, non-hormonal medicines or targeted support for sleep and mental health. Each has potential benefits, limitations and contraindications.
When should you seek medical advice?
Book an appointment if symptoms affect sleep, work, relationships, sexual health or mental wellbeing. Seek assessment for:
- very heavy or prolonged periods;
- bleeding between periods or after sex;
- periods stopping before age 45, particularly before 40;
- new pelvic pain;
- persistent palpitations, breathlessness or unexplained fatigue;
- any sudden, severe or unusual symptom.
The OVEA perspective: connecting symptoms with context
One isolated result cannot describe a hormonal transition. Understanding perimenopause means connecting cycle changes, symptoms, sleep, medical history, lifestyle and — when clinically relevant — biological data.
OVEA is building preventive healthcare designed around women, helping each woman understand her health as a whole and identify what deserves attention. Join the waitlist to discover OVEA first.
Reviewed by the OVEA medical committee