Clinical overview
The climacteric is the physiological transition from reproductive to non-reproductive life — it spans the perimenopause (the years of escalating cycle disturbance and symptoms leading up to the last period) through into the early postmenopause. Menopause itself is a single retrospective point: the permanent cessation of menstruation caused by loss of ovarian follicular activity, diagnosed only after 12 consecutive months of amenorrhoea with no other cause. The median age in most populations is around 51 years; cessation before 40 is premature ovarian insufficiency (POI) and between 40 and 45 is early menopause — distinctions that matter enormously because these younger women need oestrogen replacement for protection, not merely symptom relief.
This is an HOTS objective because the central skill is not making the diagnosis — which in a woman over 45 is clinical and needs no blood test — but weighing the benefits and risks of hormone replacement therapy (HRT) for the individual in front of you, and counselling her accordingly. The climacteric is far more than hot flushes: it brings vasomotor instability, the genitourinary syndrome of menopause, psychological and cognitive symptoms, and longer-term consequences for bone (Osteoporosis) and cardiovascular health. Modern practice has also been reshaped by a more nuanced reading of the Women's Health Initiative, the "timing hypothesis", and — within the last few years — an entirely new non-hormonal drug class targeting the hypothalamic thermostat directly. This chapter covers presentation, impact, assessment, and a contemporary, individualised management approach. It links to Osteoporosis, Contraceptive modalities (contraception is still needed in the perimenopause), and Hyperandrogenism.
Core knowledge
Staging and definitions
The STRAW+10 system stages reproductive ageing from the menstrual cycle, FSH, and ovarian markers:
- Reproductive — regular cycles.
- Menopause transition (perimenopause) — early: variable cycle length (persistent ≥7-day difference); late: an interval of amenorrhoea ≥60 days and rising, fluctuating FSH.
- Postmenopause — from the final menstrual period onward.
Key terms: perimenopause (the symptomatic transition, ending 12 months after the last period), menopause (retrospective, 12 months amenorrhoea), POI (<40 years), early menopause (40–45), and iatrogenic/surgical menopause (after bilateral oophorectomy, chemotherapy, or pelvic radiotherapy — often abrupt and severe).
The endocrinology
The driver is progressive depletion of the ovarian follicle pool. As follicles are exhausted:
- Inhibin B and anti-Müllerian hormone (AMH) fall first, removing inhibition of the pituitary.
- FSH rises (and later LH), at first intermittently — which is why a single FSH in the perimenopause is unreliable.
- Oestradiol fluctuates — sometimes high, sometimes low — before settling low in the postmenopause, when the dominant oestrogen becomes oestrone from peripheral aromatisation of adrenal androgens in adipose tissue.
The wildly fluctuating oestradiol of the perimenopause explains why this phase is often the most symptomatic, paradoxically more so than the stable low-oestrogen postmenopause.
Figure B3.1 — STRAW+10 staging, ovarian marker changes, fluctuating FSH and oestradiol, diagnostic testing rules, and perimenopausal contraception timing.