Menopause and Perimenopause

Introduction

Menopause is the permanent cessation of menstruation resulting from loss of ovarian follicular activity. It is a retrospective clinical diagnosis, confirmed after 12 consecutive months of amenorrhoea in a woman of the expected age, with no other cause identified. The average age of natural menopause in the UK is 51, with the normal range roughly 45-55.¹

Perimenopause (the menopausal transition) refers to the period leading up to the final menstrual period, characterised by fluctuating and eventually declining ovarian hormone production, irregular cycles, and the onset of menopausal symptoms - it can last several years, and is often when women first present to primary care.

Premature ovarian insufficiency (POI) describes menopause occurring before the age of 40, and early menopause describes onset between 40 and 45; both carry additional long-term health implications discussed below.

Pathophysiology

Menopause reflects the natural exhaustion of the finite pool of ovarian follicles present from birth. As the number of remaining follicles falls, they become less responsive to FSH, oestradiol production falls, and, without negative feedback, FSH (and to a lesser extent LH) rises progressively - initially fluctuating during the perimenopause, then persistently elevated after menopause.²

Falling oestrogen underlies essentially all menopausal symptoms and long-term health changes: it destabilises hypothalamic thermoregulation (causing vasomotor symptoms), reduces collagen and blood flow in urogenital tissue (causing genitourinary symptoms), accelerates bone resorption relative to formation (causing osteoporosis risk), and removes a protective effect on the vascular endothelium and lipid profile (contributing to rising cardiovascular risk after menopause).

Clinical features

Symptoms vary widely in severity and duration between women, and often begin during the perimenopause before periods have stopped altogether.¹

Vasomotor

Hot flushes and night sweats affect up to 80% of women and are often the most troublesome symptom, typically lasting several years but occasionally persisting for a decade or more.

Genitourinary syndrome of menopause (GSM)

Vaginal dryness, itching and dyspareunia from vaginal atrophy, alongside urinary frequency, urgency and recurrent UTIs from urethral and bladder trigone atrophy - these symptoms often develop later than vasomotor symptoms and, unlike them, tend to persist or worsen without treatment.

Psychological

Low mood, anxiety, irritability, brain fog and poor concentration are common and frequently under-recognised as menopausal in origin, sometimes leading to misdiagnosis as a primary mood disorder.

Other

• Sleep disturbance (often secondary to night sweats, but also independent)
• Joint aches and myalgia
• Reduced libido
• Irregular, then absent, periods during the transition itself
• Skin and hair changes (dryness, thinning)

Diagnosis

In women aged 45 or over with typical symptoms, menopause is diagnosed clinically without the need for blood tests.¹ Perimenopause is diagnosed from vasomotor symptoms plus irregular periods in this age group; menopause itself is confirmed after 12 months of amenorrhoea.

When to check FSH

• Women aged 40-45 with menopausal symptoms, including a change in menstrual cycle
• Women under 40 with suspected premature ovarian insufficiency - two FSH levels 4-6 weeks apart, both in the menopausal range, support the diagnosis
• Women without a uterus (e.g. previous hysterectomy) where menstrual pattern cannot guide diagnosis
• Women on hormonal contraception that masks the natural cycle

Management

Management is individualised, balancing symptom severity, personal risk factors, and patient preference, with holistic discussion of lifestyle, HRT and non-hormonal options.³

Lifestyle measures

Regular exercise, weight management, reducing alcohol and caffeine, smoking cessation, and layered clothing/cooling strategies can meaningfully reduce vasomotor symptom burden and should be discussed regardless of whether HRT is also used.

Hormone replacement therapy (HRT)

HRT is the most effective treatment for vasomotor and many other menopausal symptoms and is first-line for women without contraindications who have troublesome symptoms.³

Why progestogen matters: unopposed systemic oestrogen in a woman with a uterus causes endometrial hyperplasia and increases the risk of endometrial cancer. Progestogen is added to protect the endometrium - it is not needed if the uterus has been removed.

Non-hormonal options

For women who cannot or choose not to take HRT: SSRIs/SNRIs (e.g. venlafaxine) or clonidine can reduce vasomotor symptoms, though generally less effectively than HRT. Vaginal moisturisers and lubricants help with vaginal dryness. Cognitive behavioural therapy has a good evidence base for menopausal symptoms, including low mood and sleep disturbance.

Risks and contraindications of HRT

The risk-benefit balance of HRT should be discussed individually, but for most women who start HRT around the time of menopause, the benefits outweigh the risks.³

Contraception around the menopause

Fertility declines sharply in the perimenopause but does not disappear the moment periods become irregular, and unplanned pregnancy at this age carries higher maternal and fetal risk. Contraception is therefore continued for a defined period after the last menstrual period (LMP), with the duration depending on age:⁵

Premature ovarian insufficiency

Premature ovarian insufficiency (POI) is menopause before age 40, affecting around 1% of women. Causes include idiopathic (most common), autoimmune, genetic (e.g. Turner syndrome, fragile X premutation), and iatrogenic (chemotherapy, radiotherapy, oophorectomy).⁴

Because these women face many more years of oestrogen deficiency than women with natural-age menopause, HRT (or the combined oral contraceptive pill as an alternative) is recommended at least until the average age of natural menopause (51) to protect against osteoporosis and cardiovascular disease - this is replacement rather than the same risk-benefit discussion applied to older women, and should not be withheld on the same grounds.

Long-term health after menopause

Beyond acute symptoms, the fall in oestrogen has lasting effects that should be part of routine discussion at menopause.¹

• Osteoporosis: accelerated bone loss in the years after menopause; consider bone health advice, calcium/vitamin D, and DEXA scanning if additional risk factors are present
• Cardiovascular disease: risk rises after menopause as the protective effect of oestrogen on lipids and the vasculature is lost
• Genitourinary syndrome of menopause: often progressive without treatment, unlike vasomotor symptoms which tend to improve with time

Prognosis

Vasomotor symptoms typically improve over several years even without treatment, though a minority of women experience them for a decade or longer. Genitourinary symptoms tend not to improve spontaneously and often need ongoing (commonly topical) treatment. With appropriate management of symptoms and attention to long-term bone and cardiovascular health, most women transition through menopause with a good quality of life, and HRT remains a safe and effective option for the majority who choose it around the time of menopause.