Pituitary apoplexy is a neurosurgical emergency — sudden haemorrhage or infarction into a pituitary adenoma causes rapid expansion within the bony sella, compressing the optic chiasm (bitemporal hemianopia), cranial nerves III, IV, VI (sudden ocular palsies — diplopia, ptosis), and potentially the hypothalamus. The clinical presentation: sudden severe headache ('thunderclap'), visual loss or diplopia, meningism, confusion. The endocrine emergency: acute panhypopituitarism from destruction of the remaining pituitary — ACTH deficiency → adrenal insufficiency → hypotension and collapse. Management: 999, IV hydrocortisone 100 mg stat (empirically for presumed adrenal insufficiency), urgent MRI (CT may miss haemorrhage), and neurosurgical team alert. Trans-sphenoidal decompression is performed if visual loss is progressive. GPs must know that any woman with known pituitary adenoma who presents with sudden severe headache requires emergency assessment.

The LH:FSH ratio is one of the most useful rapid discriminators in female hormone abnormality assessment — in a normal cycling woman, FSH and LH are roughly equal in the follicular phase. In PCOS, LH is disproportionately elevated relative to FSH (LH:FSH ratio ≥2:1, or classically ≥3:1), driven by increased GnRH pulse frequency that favours LH over FSH secretion, combined with androgen-driven sensitisation of the pituitary to GnRH. The elevated LH drives excessive ovarian androgen production from theca cells. However, the LH:FSH ratio is not required for PCOS diagnosis under the Rotterdam criteria — ultrasound-detected polycystic ovarian morphology and clinical/biochemical hyperandrogenism are the core criteria. The ratio is most useful when results are borderline or when the clinician wants additional supporting evidence for PCOS vs other causes of oligomenorrhoea.

Day 21 progesterone timing is a critical point that is frequently got wrong in clinical practice — the test is designed to detect the progesterone peak from the corpus luteum following ovulation, which occurs approximately 7 days after ovulation. In a 28-day cycle (ovulation at day 14), this peak is at day 21. However, for women with longer cycles: the progesterone should be taken 7 days before the expected next period, not on a fixed day 21. A woman with a 35-day cycle ovulates at approximately day 21, meaning her progesterone peak is at day 28 — taking the blood on day 21 of this cycle will give a falsely low result (she hasn't ovulated yet). The instruction to patients: 'If your cycle is regular, take this test one week before your next period is due.' If the cycle is irregular and unpredictable, serial progesterone measurements or a different approach (tracking with LH kits) is needed.

Premature ovarian insufficiency (POI) HRT is not elective — it is a medical necessity. The oestrogen deficiency that begins before age 40 in women with POI causes accelerated bone loss (POI carries approximately 3-fold increased hip fracture risk), premature cardiovascular disease (oestrogen-deprived women under 40 lose the normal female cardiovascular protection advantage), urogenital atrophy, sexual dysfunction, and significant quality-of-life impairment including cognitive effects and depression. HRT in POI is replacement of a physiologically absent hormone (analogous to thyroxine in hypothyroidism) — it does not carry the same risk profile as HRT started post-naturally-menopausal age in older women. The NICE NG23 menopause guidance explicitly states: 'Women with POI should be offered HRT and advised to continue it until at least the age of natural menopause (51 years).' GPs who see women with POI on no HRT should initiate a conversation about HRT at every appointment until the decision is made — non-treatment is the greater clinical risk.

The PCOS endometrial hyperplasia risk from prolonged anovulation is an important and underappreciated complication — women with PCOS who have prolonged oligomenorrhoea or amenorrhoea (fewer than 4 periods per year, or periods more than 3 months apart) accumulate unopposed oestrogen in the endometrium, as progesterone (the 'withdrawal' hormone normally produced after ovulation) is absent. Over years, this can cause endometrial hyperplasia and eventually endometrial carcinoma. The GP management principle: any woman with PCOS who is not having regular induced periods (either from ovulation or from withdrawal bleeds from progesterone or a progestogen-containing pill) should be offered a progestogen-induced withdrawal bleed every 3-4 months minimum (medroxyprogesterone acetate 10 mg OD for 10-14 days, or norethisterone 5 mg OD for 10 days). A transvaginal USS to assess endometrial thickness is indicated if the woman has not bled for 6+ months — endometrial thickness >4 mm in the absence of hormonal stimulation warrants gynaecology assessment.

The eflornithine cream (Vaniqa) is a specifically licensed topical treatment for facial hirsutism that is frequently unknown to GPs and patients — it works by irreversibly inhibiting ornithine decarboxylase, an enzyme required for hair follicle cell division and hair growth. It reduces the rate of facial hair growth rather than removing existing hair, so it must be combined with a hair removal method (shaving, waxing, laser) for full effectiveness. Application: thin film to affected facial areas BD, at least 8 hours between applications, wash hands after. Onset of effect: 4-8 weeks. If discontinued, hair growth returns to baseline within 8 weeks. Licensed indication: face and under-chin in women. It is available on NHS prescription. Combination with COCP or spironolactone produces additive antiandrogen + growth-suppression effect for maximum hirsutism control.

The transdermal oestrogen preference for HRT in women at higher cardiovascular or VTE risk is based on the first-pass hepatic effect — oral oestrogen is absorbed via the portal circulation and undergoes first-pass metabolism in the liver, stimulating hepatic production of clotting factors (particularly factors VII and X) and C-reactive protein, modestly increasing VTE risk (approximately 2-fold increase vs baseline). Transdermal oestrogen (patches or gel) bypasses hepatic first-pass metabolism entirely, delivering oestrogen directly into the systemic circulation. Multiple observational studies (the E3N cohort, the UK General Practice Research Database studies) show that transdermal oestrogen does not increase VTE risk above baseline. This difference is clinically important for: women with a personal history of VTE (on anticoagulation or off), women with factor V Leiden or other thrombophilias, obese women (BMI >30 — already at elevated VTE risk), women with migraines with aura. The MHRA and NICE NG23 explicitly state that transdermal oestrogen should be preferred in women at elevated VTE risk.

The testosterone therapy for hypoactive sexual desire disorder (HSDD) in postmenopausal women has finally received authoritative support from NICE NG23 (updated 2023) — the guideline states that testosterone should be considered for women with HSDD whose other menopause symptoms are adequately controlled by HRT but who have persistent loss of sexual desire causing personal distress. The evidence base: multiple RCTs demonstrate that transdermal testosterone at physiological female doses (approximately 5% of male dose) increases sexual desire, arousal, and satisfaction in postmenopausal women. The dosing: testosterone gel (Testogel 1% or Tostran 2% gel — both licensed for men only, used off-label for women): approximately 0.5 mL of 1% Testogel (5 mg testosterone) or 0.5 pump of Tostran applied to inner thigh or shoulder daily. Monitor: serum total testosterone at 3-6 months (target upper normal female range, not male range). Side effects at physiological doses: mild increase in acne in some women; no significant cardiovascular or breast cancer effects at these doses. Long-term data reassuring.

The annual PCOS progestogen withdrawal bleed protocol is a preventive intervention that significantly reduces the risk of endometrial hyperplasia — women with PCOS who are not on the COCP, Mirena IUS, or having regular natural menstruation should receive a progestogen course every 3-4 months to induce a withdrawal bleed. The regimen: medroxyprogesterone acetate (Provera) 10 mg OD for 10-14 days, or norethisterone 5 mg OD for 10 days. A withdrawal bleed is expected 2-7 days after completing the course. If no bleed occurs: do a pregnancy test (if sexually active) and arrange USS to assess endometrial thickness. This is documented in NICE CG156 (PCOS) and the Endocrine Society PCOS guidelines. GPs should code this progestogen prescription in the EMIS/SystmOne record linked to the PCOS diagnosis to facilitate systematic recall.