5. Genitourinary Syndrome of Menopause (GSM)
Pedagogy: This lesson uses progressive-disease framing — teaching clinicians to recognise GSM as a chronic condition requiring ongoing management, not a self-limiting complaint.
Learning Objectives
- Define GSM and distinguish it from the older term vulvovaginal atrophy (VVA)
- Describe the three symptom domains: genital, urinary, and sexual
- Explain the pathophysiology: oestrogen deficiency in vulvovaginal and lower urinary tract tissues
- Recognise that GSM is under-diagnosed due to patient embarrassment and clinician failure to ask
Key Facts
Definition and Prevalence
GSM encompasses the genital, urinary, and sexual symptoms resulting from oestrogen deficiency in vulvovaginal and lower urinary tract tissues. It affects over 50% of postmenopausal women. Unlike VMS, GSM is progressive and does not resolve spontaneously — it typically worsens without treatment (1,2).
Symptom Domains
| Domain | Symptoms |
|---|---|
| Genital | Vaginal dryness, burning, irritation, discharge changes |
| Urinary | Frequency, urgency, dysuria, recurrent UTI |
| Sexual | Dyspareunia, reduced lubrication, post-coital bleeding |
Pathophysiology
Oestrogen receptors are densely expressed in vulvovaginal epithelium, urethra, and bladder trigone. With oestrogen withdrawal: vaginal epithelium thins, glycogen content decreases, lactobacilli decline, vaginal pH rises (from 3.5-4.5 to 6-8), and the microbiome shifts to pathogenic organisms, increasing UTI susceptibility (1).
Under-Recognition
GSM is significantly under-diagnosed. Barriers include: patient embarrassment; normalisation of symptoms; clinicians not asking about urogenital symptoms; and focus on VMS at the expense of other symptom domains. Proactive screening at every menopause consultation is essential (2).
Clinical Pearl GSM is PROGRESSIVE and CHRONIC. It will not resolve on its own. Every menopause consultation should include a proactive screen for vaginal dryness, dyspareunia, and urinary symptoms.
Clinical Pearl Many women with 'recurrent UTIs' in the postmenopausal period actually have GSM-related urinary symptoms. Vaginal oestrogen may be more effective than repeated antibiotics.
Case-Based Examples
Case 1: 58-year-old with 'recurrent UTIs'
Presentation: A 58-year-old presents with her fourth 'UTI' this year. Urine cultures have been mixed — only 2 of 4 grew significant organisms. She also mentions vaginal discomfort.
Question: What diagnosis should you consider and what is your management approach?
Model Answer: Consider GSM as the underlying cause. Recurrent UTI-like symptoms with inconsistent cultures in a postmenopausal woman are classic. Examine: look for vaginal atrophy (pale, thin epithelium, loss of rugae, narrowed introitus). Management: vaginal oestrogen (e.g. estriol cream or Vagifem pessary) — nightly for 2 weeks then twice weekly long-term. This treats both the vaginal and urinary symptoms. No progestogen needed (negligible systemic absorption). Add a non-hormonal vaginal moisturiser. Review at 3 months. If genuine recurrent UTI: consider low-dose prophylactic antibiotic, but vaginal oestrogen should be first-line.
Case 2: Breast cancer survivor with severe vaginal dryness on an aromatase inhibitor
Presentation: A 60-year-old on letrozole with severe vaginal dryness and dyspareunia. She has stopped sexual activity due to pain. Non-hormonal moisturisers have been insufficient.
Question: Discuss the options including the controversy around vaginal oestrogen in this context.
Model Answer: Non-hormonal options first: vaginal moisturisers (Replens, YES VM) used regularly (not just before intercourse), water-based lubricants. If insufficient (as here): discuss low-dose vaginal oestrogen. Most guidelines (IMS, NAMS) consider low-dose vaginal oestrogen safe in breast cancer survivors due to minimal systemic absorption. However, with aromatase inhibitors specifically, there is a pharmacological conflict — AIs aim to suppress all oestrogen. Some studies show transient serum oestradiol rises. This decision MUST involve her oncologist. Alternatives: vaginal prasterone (DHEA) — converted locally to oestrogen and testosterone; ospemifene (oral SERM) — not widely used in UK. Laser therapy has limited evidence and NICE makes no recommendation.
Self-Assessment Questions
PLAB/MLA Natural history of GSM
Which statement about GSM is correct?
A. GSM resolves spontaneously like VMS
B. GSM is progressive and requires ongoing treatment
C. GSM affects only 10% of postmenopausal women
D. Systemic HRT always resolves GSM completely
Answer: B. GSM is progressive and chronic, affecting >50% of postmenopausal women. Some women on systemic HRT still require additional topical vaginal oestrogen.
MRCGP Vaginal oestrogen: progestogen requirement
A 62-year-old not on systemic HRT is prescribed vaginal oestrogen for GSM. Does she need progestogen for endometrial protection?
A. Yes — all oestrogen therapy requires progestogen
B. No — low-dose vaginal oestrogen has negligible systemic absorption and progestogen is not required
C. Only if she uses it for more than 1 year
D. Only if she has a uterus and uses high-dose vaginal oestrogen
Answer: B. Low-dose vaginal oestrogen preparations (Vagifem, estriol creams at standard doses) have minimal systemic absorption. Progestogen is not required, and treatment can be continued long-term (NICE NG23, BMS 2026).
Professor Vaginal microbiome changes and UTI pathogenesis in GSM
Explain the pathophysiological link between oestrogen deficiency, vaginal microbiome changes, and recurrent UTI in postmenopausal women.
A. Oestrogen deficiency has no effect on the vaginal microbiome
B. Oestrogen depletion reduces glycogen, leading to lactobacillus decline, rising vaginal pH, and colonisation by uropathogens — vaginal oestrogen reverses this cascade
C. UTIs in postmenopausal women are always caused by anatomical changes
D. The microbiome is irrelevant to UTI pathogenesis
Answer: B. Oestrogen maintains vaginal epithelial glycogen stores, which fuel lactobacillus growth. Lactobacilli produce lactic acid, maintaining acidic pH (3.5-4.5) and inhibiting uropathogen colonisation. Post-menopause: glycogen falls, lactobacilli decline, pH rises to 6-8, and uropathogens (E. coli, Klebsiella) colonise the vaginal introitus and periurethral area, ascending to cause UTI. Vaginal oestrogen restores glycogen, lactobacilli, and acidic pH, reducing UTI recurrence. This is a classic example of microbiome-mediated disease mechanism with a targeted therapeutic intervention.
Take-Away Messages
- GSM is progressive and chronic — it does NOT resolve spontaneously like VMS
- Three domains: genital (dryness, irritation), urinary (frequency, recurrent UTI), sexual (dyspareunia)
- Proactive screening is essential — patients rarely volunteer urogenital symptoms
- Vaginal oestrogen has negligible systemic absorption; progestogen is NOT required
- Recurrent UTIs in postmenopausal women may be GSM-related — vaginal oestrogen is often more effective than antibiotics