Gynaecology — MCQs
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A 35-year-old woman with von Willebrand disease presents with heavy menstrual bleeding that significantly affects her quality of life. She uses 16 super-absorbent tampons per period and has haemoglobin of 88 g/L. She wishes to avoid hormonal contraception due to a family history of breast cancer. What is the most appropriate initial pharmacological management?
A 46-year-old woman presents with a 7-month history of heavy irregular bleeding. She reports cycles varying from 18 to 45 days with unpredictable heavy flow. She experiences hot flushes and night sweats. Haemoglobin is 108 g/L, TSH is normal. Transvaginal ultrasound shows a 6mm endometrium and normal ovaries. What is the most appropriate management approach?
A 22-year-old woman presents with sudden onset severe right-sided pelvic pain and vaginal bleeding. She has a copper intrauterine device in situ for contraception. Her LMP was 8 weeks ago. Urine pregnancy test is positive. She is haemodynamically stable. Transvaginal ultrasound shows an empty uterus with the IUD correctly positioned and a 25mm right adnexal mass with a hyperechoic ring. Free fluid is visible in the pouch of Douglas. Beta-hCG is 3,200 IU/L. What does this clinical scenario illustrate about contraceptive failure?
A 37-year-old woman with heavy menstrual bleeding has tried tranexamic acid and mefenamic acid with minimal improvement. She has completed her family and does not wish to use hormonal treatments. Pelvic examination and ultrasound are normal with no structural abnormality. Her haemoglobin is 102 g/L. She is significantly bothered by the heavy bleeding. What is the most appropriate next management option?
What is the mechanism by which mefenamic acid reduces menstrual blood loss in women with heavy menstrual bleeding?
A 44-year-old woman with heavy menstrual bleeding has had a levonorgestrel intrauterine system in situ for 18 months. She reports significant improvement initially, but now her periods have become heavy again over the past 3 months. Examination reveals a bulky uterus. What is the most appropriate initial investigation?
A 33-year-old woman is being treated with intramuscular methotrexate for an unruptured tubal ectopic pregnancy. Her initial beta-hCG was 1,850 IU/L. On day 4 post-methotrexate, she develops increased right-sided abdominal pain with guarding but remains haemodynamically stable. Beta-hCG on day 4 is 2,100 IU/L. What is the most likely explanation for her symptoms?
A 48-year-old woman presents with heavy menstrual bleeding lasting 10 days each cycle. She has passed large clots and experiences flooding. Blood tests show haemoglobin 95 g/L, ferritin 8 ng/mL, and TSH 2.1 mU/L. Transvaginal ultrasound reveals a uniformly enlarged uterus measuring 14cm with heterogeneous myometrium but no discrete masses. Endometrial thickness is 8mm. What is the most likely diagnosis?
A 29-year-old woman presents with 6 weeks amenorrhoea and right lower abdominal pain. Beta-hCG is 2,400 IU/L. Transvaginal ultrasound shows an empty uterus with 15mm endometrial thickness and no adnexal mass visible. She is haemodynamically stable with minimal pain. A repeat beta-hCG 48 hours later is 2,550 IU/L. What is the most appropriate next step in management?
A 34-year-old woman with polycystic ovary syndrome presents with a 15-month history of oligomenorrhoea with occasional very heavy bleeding episodes. She experiences a period approximately every 3-4 months, lasting 10-12 days with flooding and clots. BMI is 32 kg/m². She is not sexually active. Pelvic examination is normal. What is the underlying pathophysiological mechanism most likely responsible for her heavy menstrual bleeding?
Gynaecology UK Medical PG Practice Questions and MCQs
Question 81: A 35-year-old woman with von Willebrand disease presents with heavy menstrual bleeding that significantly affects her quality of life. She uses 16 super-absorbent tampons per period and has haemoglobin of 88 g/L. She wishes to avoid hormonal contraception due to a family history of breast cancer. What is the most appropriate initial pharmacological management?
- A. Tranexamic acid 1g three times daily during menstruation
- B. Desmopressin (DDAVP) administered intranasally at the onset of menstruation
- C. Combined tranexamic acid and desmopressin therapy (Correct Answer)
- D. Mefenamic acid 500mg three times daily during menstruation
- E. Factor VIII concentrate infusion before each menstrual period
Explanation: ***Combined tranexamic acid and desmopressin therapy*** - For patients with **von Willebrand disease (vWD)** and severe menorrhagia (indicated by heavy tampon use and **anemia**), combined therapy is the most effective non-hormonal approach as it addresses both **clot formation** and **clot stability**. - **Desmopressin (DDAVP)** increases endogenous levels of vWF and Factor VIII, while **tranexamic acid** prevents the breakdown of clots within the endometrial lining, offering a synergistic effect. *Tranexamic acid 1g three times daily during menstruation* - While it is a potent **antifibrinolytic** that reduces menstrual blood loss by stabilizing clots, it does not correct the underlying **vWF deficiency**. - In the context of known vWD with significant **iron deficiency anemia**, monotherapy is often insufficient for optimal control compared to dual therapy. *Desmopressin (DDAVP) administered intranasally at the onset of menstruation* - DDAVP helps release **vWF and Factor VIII** stores, but its effect is temporary and may not provide sustained control throughout the entire menstrual period, especially in severe cases. - Used alone, it is generally less effective for **heavy menstrual bleeding** due to vWD than when paired with an antifibrinolytic agent like tranexamic acid. *Mefenamic acid 500mg three times daily during menstruation* - **Mefenamic acid** is an NSAID that reduces prostaglandin levels, thereby decreasing menstrual flow, but it is significantly less effective than tranexamic acid for treating **coagulopathy-related bleeding**. - It also carries a theoretical risk of interfering with **platelet aggregation**, which could potentially worsen bleeding tendencies in a patient with vWD. *Factor VIII concentrate infusion before each menstrual period* - **Factor VIII or vWF concentrates** are usually reserved for surgical prophylaxis, severe bleeding episodes, or life-threatening bleeds rather than routine management of **menorrhagia**. - This treatment is invasive, expensive, and not considered **first-line pharmacological management** for chronic menstrual control in vWD when other options are available.
Question 82: A 46-year-old woman presents with a 7-month history of heavy irregular bleeding. She reports cycles varying from 18 to 45 days with unpredictable heavy flow. She experiences hot flushes and night sweats. Haemoglobin is 108 g/L, TSH is normal. Transvaginal ultrasound shows a 6mm endometrium and normal ovaries. What is the most appropriate management approach?
- A. Reassure and manage conservatively with iron supplementation
- B. Commence cyclical oral progestogen therapy
- C. Arrange outpatient hysteroscopy and endometrial biopsy (Correct Answer)
- D. Start combined oral contraceptive pill
- E. Prescribe tranexamic acid for heavy days only
Explanation: ***Arrange outpatient hysteroscopy and endometrial biopsy*** - In women aged **≥45 years** presenting with persistent **heavy irregular bleeding** or a significant change in pattern, international guidelines recommend **endometrial sampling** to rule out **endometrial hyperplasia** or **carcinoma**. - Although the **endometrial thickness of 6mm** is within a benign range for postmenopausal women on HRT, it does not reliably exclude focal **endometrial pathology** or **atypia** in the context of persistent, irregular perimenopausal bleeding, making a biopsy essential. *Reassure and manage conservatively with iron supplementation* - While **iron supplementation** is necessary to address the **anaemia** (Hb 108 g/L), this approach fails to investigate the underlying cause of the **heavy irregular bleeding**. - Reassurance alone is inappropriate and potentially dangerous for a 46-year-old with such symptoms, as it could delay the diagnosis of serious **endometrial pathology**. *Commence cyclical oral progestogen therapy* - **Cyclical oral progestogens** can help regulate bleeding in perimenopause, but they should not be initiated as a primary treatment before **endometrial sampling** in a woman over 45 with persistent abnormal uterine bleeding. - Starting hormonal therapy without a biopsy risks masking symptoms and delaying the diagnosis of conditions like **endometrial hyperplasia** or **cancer**. *Start combined oral contraceptive pill* - The **combined oral contraceptive pill (COCP)** can effectively manage both bleeding and perimenopausal symptoms but is contraindicated as a first step before **endometrial investigation** in this age group and clinical scenario. - Prescribing a COCP without excluding **endometrial pathology** could obscure a significant diagnosis and delay appropriate management. *Prescribe tranexamic acid for heavy days only* - **Tranexamic acid** is an effective non-hormonal treatment for reducing **heavy menstrual bleeding**, but it does not address the **irregularity** of the cycles or the underlying diagnostic requirement. - This treatment is purely symptomatic and does not investigate the crucial **7-month history** of unpredictable bleeding in a woman over 45, which mandates histological assessment.
Question 83: A 22-year-old woman presents with sudden onset severe right-sided pelvic pain and vaginal bleeding. She has a copper intrauterine device in situ for contraception. Her LMP was 8 weeks ago. Urine pregnancy test is positive. She is haemodynamically stable. Transvaginal ultrasound shows an empty uterus with the IUD correctly positioned and a 25mm right adnexal mass with a hyperechoic ring. Free fluid is visible in the pouch of Douglas. Beta-hCG is 3,200 IU/L. What does this clinical scenario illustrate about contraceptive failure?
- A. The copper IUD increases the risk of ectopic pregnancy compared to no contraception
- B. When pregnancy occurs with an IUD in situ, the relative risk of it being ectopic is increased (Correct Answer)
- C. IUDs prevent intrauterine pregnancies but provide no protection against ectopic pregnancies
- D. The IUD should be removed immediately to reduce ectopic pregnancy risk
- E. Copper IUDs are less effective at preventing ectopic pregnancy than hormonal IUDs
Explanation: ***When pregnancy occurs with an IUD in situ, the relative risk of it being ectopic is increased*** - While IUDs significantly lower the **overall risk** of pregnancy, they are more effective at preventing **intrauterine implantation** than extrauterine implantation. - Because of this differential efficacy, if a patient becomes pregnant with an IUD in situ, there is a much higher **proportion (relative risk)** that the pregnancy will be **ectopic** compared to the general population. *The copper IUD increases the risk of ectopic pregnancy compared to no contraception* - This is false because any form of effective contraception, including the **copper IUD**, reduces the **absolute risk** of ectopic pregnancy by preventing fertilization. - A woman using an IUD has a lower total chance of having an **ectopic pregnancy** than a woman using no contraception at all. *IUDs prevent intrauterine pregnancies but provide no protection against ectopic pregnancies* - IUDs do provide protection against **ectopic pregnancies** by acting as a contraceptive and preventing the initial **conception** from occurring. - However, the protection is simply less complete than its protection against **intrauterine pregnancies**, leading to the observed shift in relative frequency. *The IUD should be removed immediately to reduce ectopic pregnancy risk* - Once an **ectopic pregnancy** is already established and visualized on **ultrasound**, removing the IUD does not treat or resolve the ectopic gestation. - Management should focus on the **adnexal mass** (surgical or medical with methotrexate) rather than the **intrauterine** contraceptive device location. *Copper IUDs are less effective at preventing ectopic pregnancy than hormonal IUDs* - Both the **copper IUD** and the **levonorgestrel-releasing intrauterine system (LNG-IUS)** are highly effective at preventing both types of pregnancy. - There is no clinical evidence provided in this scenario to suggest a superiority of **hormonal IUDs** over copper ones specifically regarding **ectopic pregnancy** prevention rates.
Question 84: A 37-year-old woman with heavy menstrual bleeding has tried tranexamic acid and mefenamic acid with minimal improvement. She has completed her family and does not wish to use hormonal treatments. Pelvic examination and ultrasound are normal with no structural abnormality. Her haemoglobin is 102 g/L. She is significantly bothered by the heavy bleeding. What is the most appropriate next management option?
- A. Offer endometrial ablation (Correct Answer)
- B. Commence oral norethisterone (5mg three times daily) days 5-26 of cycle
- C. Arrange hysterectomy
- D. Trial of combined oral contraceptive pill despite her preference
- E. Refer for uterine artery embolization
Explanation: ***Offer endometrial ablation*** - For women who have **completed their family** and find medical management unsuccessful or undesirable, **endometrial ablation** is a recommended surgical option for heavy menstrual bleeding without structural pathology. - It is less invasive than a hysterectomy and is suitable for patients, like this woman, who have specifically **declined hormonal treatments**. *Commence oral norethisterone (5mg three times daily) days 5-26 of cycle* - This is a **progestogen-based hormonal treatment** which the patient has already stated she does not wish to use. - While effective for cycle control, it does not address her preference for **non-hormonal** management. *Arrange hysterectomy* - **Hysterectomy** is a definitive surgical treatment but is more invasive and associated with longer **recovery times** and higher complication rates. - It is usually considered if **endometrial ablation** has failed, is contraindicated, or if the patient expresses a specific preference for it after discussing other surgical options. *Trial of combined oral contraceptive pill despite her preference* - Medical ethics and **NICE guidelines** emphasize the importance of respecting **patient preference**; offering a hormonal treatment she has explicitly declined is inappropriate. - The **combined oral contraceptive pill** is a hormonal method which she has excluded from her chosen management path. *Refer for uterine artery embolization* - **Uterine artery embolization (UAE)** is primarily indicated for the treatment of **heavy menstrual bleeding** associated with **large fibroids**. - Since this patient has a **normal ultrasound** with no structural abnormalities, UAE is not an appropriate clinical intervention.
Question 85: What is the mechanism by which mefenamic acid reduces menstrual blood loss in women with heavy menstrual bleeding?
- A. Inhibition of fibrinolysis in the endometrium
- B. Reduction in endometrial prostaglandin synthesis (Correct Answer)
- C. Suppression of gonadotrophin release
- D. Induction of endometrial atrophy
- E. Enhancement of platelet aggregation
Explanation: ***Reduction in endometrial prostaglandin synthesis***- **Mefenamic acid** is an **NSAID** that inhibits **cyclooxygenase (COX) enzymes**, leading to decreased production of **prostaglandins** (PGE2, PGF2α) in the endometrium.- Excess prostaglandins cause **vasodilation** and increased blood loss during menstruation, so reducing their synthesis helps to decrease heavy menstrual bleeding.*Inhibition of fibrinolysis in the endometrium*- This is the primary mechanism of action for **tranexamic acid**, an **antifibrinolytic agent**, which works by preventing the breakdown of existing blood clots.- Mefenamic acid does not directly inhibit the **fibrinolytic system** in the endometrium.*Suppression of gonadotrophin release*- This mechanism is characteristic of **hormonal treatments** such as combined oral contraceptives or GnRH agonists, which act on the **hypothalamic-pituitary-ovarian axis**.- Mefenamic acid's action is localized to the endometrium, affecting prostaglandin pathways rather than systemic hormonal regulation.*Induction of endometrial atrophy*- This effect is typically achieved by **progestogen-releasing intrauterine systems** (e.g., LNG-IUS) or continuous progestogen therapy, which thin the endometrial lining.- Mefenamic acid does not cause structural changes or **atrophy** of the endometrium; it primarily modulates biochemical pathways.*Enhancement of platelet aggregation*- Mefenamic acid, like other NSAIDs, generally has a mild **inhibitory effect on platelet function** by suppressing thromboxane A2, rather than enhancing it.- Therefore, enhancing platelet aggregation is not the mechanism by which mefenamic acid reduces menstrual blood loss.
Question 86: A 44-year-old woman with heavy menstrual bleeding has had a levonorgestrel intrauterine system in situ for 18 months. She reports significant improvement initially, but now her periods have become heavy again over the past 3 months. Examination reveals a bulky uterus. What is the most appropriate initial investigation?
- A. Serum beta-hCG to exclude pregnancy
- B. Transvaginal ultrasound to check LNG-IUS position and assess uterine pathology (Correct Answer)
- C. Endometrial biopsy to exclude malignancy
- D. Hysteroscopy and LNG-IUS removal
- E. Full blood count and coagulation screen
Explanation: ***Transvaginal ultrasound to check LNG-IUS position and assess uterine pathology*** - The return of heavy bleeding after 18 months of efficacy suggests **LNG-IUS displacement** or the development of structural pathology like **fibroids or adenomyosis**. - A **transvaginal ultrasound** is the gold standard for verifying correct device placement and evaluating the **bulky uterus** for underlying pathology. *Serum beta-hCG to exclude pregnancy* - While **pregnancy** should be considered in women of reproductive age, it is less likely to present as a return of heavy menstrual patterns compared to structural issues. - It does not address the physical finding of a **bulky uterus** or investigate the primary cause of system failure. *Endometrial biopsy to exclude malignancy* - While age 44 is near the threshold for **endometrial cancer** screening, clinical suspicion points first to mechanical failure or structural changes. - **Endometrial biopsy** is usually performed after ultrasound results confirm an increased **endometrial thickness** or other risk factors. *Hysteroscopy and LNG-IUS removal* - **Hysteroscopy** is an invasive procedure and should not be the first-line investigation when imaging can non-invasively detect **device displacement**. - Removal of the device is premature before confirming it is the cause of the issue; it might still be salvageable or need targeted replacement. *Full blood count and coagulation screen* - A **full blood count** is helpful to assess the degree of **anemia** caused by bleeding, but it does not diagnose the underlying cause of treatment failure. - **Coagulation screens** are typically indicated if heavy bleeding has been lifelong or if there is a strong family history, not for sudden recurrence with a **bulky uterus**.
Question 87: A 33-year-old woman is being treated with intramuscular methotrexate for an unruptured tubal ectopic pregnancy. Her initial beta-hCG was 1,850 IU/L. On day 4 post-methotrexate, she develops increased right-sided abdominal pain with guarding but remains haemodynamically stable. Beta-hCG on day 4 is 2,100 IU/L. What is the most likely explanation for her symptoms?
- A. Tubal rupture requiring immediate laparoscopy
- B. Methotrexate treatment failure requiring second dose
- C. Separation pain from tubal abortion (Correct Answer)
- D. Methotrexate-induced gastritis
- E. Urinary tract infection
Explanation: ***Separation pain from tubal abortion***- This phenomenon typically occurs **3-7 days** after methotrexate administration as the pregnancy detaches from the tubal wall, causing **tubal distension**.- The patient remains **haemodynamically stable** despite symptoms of guarding or peritonism, and an initial **hCG rise** on day 4 is a common, non-diagnostic finding.*Tubal rupture requiring immediate laparoscopy*- Rupture is usually associated with significant **haemodynamic instability** (tachycardia, hypotension) and signs of **intra-abdominal hemorrhage**.- While pain and guarding are present, the stability of this patient and the timing post-injection make separation pain more statistically likely in the absence of shock.*Methotrexate treatment failure requiring second dose*- Treatment failure is defined by a **less than 15% fall** in beta-hCG between **day 4 and day 7** of treatment.- It is impossible to diagnose failure on day 4 alone because a transient **initial rise** in hCG is expected as trophoblastic cells die and release the hormone.*Methotrexate-induced gastritis*- Although methotrexate can cause gastrointestinal side effects, it typically manifests as **nausea** or **stomatitis** rather than focal lower abdominal pain with guarding.- The location of the pain in the **right-sided lower abdomen** is more consistent with the site of the ectopic pregnancy than gastric irritation.*Urinary tract infection*- A **UTI** would typically present with **dysuria**, frequency, or suprapubic tenderness rather than guarding in the adnexal region.- Clinical suspicion should remain on the known **ectopic pregnancy** given the recent medical management and the specific timeline of the abdominal symptoms.
Question 88: A 48-year-old woman presents with heavy menstrual bleeding lasting 10 days each cycle. She has passed large clots and experiences flooding. Blood tests show haemoglobin 95 g/L, ferritin 8 ng/mL, and TSH 2.1 mU/L. Transvaginal ultrasound reveals a uniformly enlarged uterus measuring 14cm with heterogeneous myometrium but no discrete masses. Endometrial thickness is 8mm. What is the most likely diagnosis?
- A. Endometrial hyperplasia
- B. Adenomyosis (Correct Answer)
- C. Multiple small intramural fibroids
- D. Endometrial polyp
- E. Endometrial carcinoma
Explanation: ***Adenomyosis***- The ultrasound finding of a **uniformly enlarged uterus** with **heterogeneous myometrium** but no discrete masses is highly characteristic of adenomyosis.- It commonly presents in women in their 40s with **heavy menstrual bleeding**, **iron-deficiency anaemia**, and a "globular" uterus on examination.*Endometrial hyperplasia*- This condition typically presents with a significantly **thickened endometrial stripe** (usually >14mm in premenopausal women), whereas this patient's thickness is 8mm.- While it causes heavy bleeding, it does not typically cause a **uniformly enlarged, heterogeneous myometrium**.*Multiple small intramural fibroids*- Fibroids (leiomyomas) usually appear as **discrete, well-circumscribed, hypoechoic masses** on ultrasound rather than diffuse heterogeneity.- While they cause uterine enlargement, the enlargement is often **irregular or nodular** rather than uniform.*Endometrial polyp*- A polyp would appear as a **focal echogenic mass** within the endometrial cavity, often with a visible vascular pedicle on Doppler.- Polyps cause intermenstrual or heavy bleeding but do not lead to **diffuse uterine enlargement** or myometrial changes.*Endometrial carcinoma*- This diagnosis usually presents with a **thickened, irregular endometrium** or a distinct intrauterine mass, especially in a postmenopausal setting.- Although the patient is 48, her **endometrial thickness of 8mm** and the specific myometrial findings make adenomyosis much more likely.
Question 89: A 29-year-old woman presents with 6 weeks amenorrhoea and right lower abdominal pain. Beta-hCG is 2,400 IU/L. Transvaginal ultrasound shows an empty uterus with 15mm endometrial thickness and no adnexal mass visible. She is haemodynamically stable with minimal pain. A repeat beta-hCG 48 hours later is 2,550 IU/L. What is the most appropriate next step in management?
- A. Arrange diagnostic laparoscopy (Correct Answer)
- B. Administer intramuscular methotrexate
- C. Commence expectant management with weekly beta-hCG monitoring
- D. Repeat transvaginal ultrasound in 48-72 hours
- E. Perform uterine evacuation for presumed miscarriage
Explanation: ***Arrange diagnostic laparoscopy***- The patient has a **pregnancy of unknown location (PUL)** with a **beta-hCG level (2,400-2,550 IU/L)** well above the **discriminatory zone** (usually 1,500-2,000 IU/L), where an intrauterine pregnancy should be visible on ultrasound.- A **suboptimal rise in beta-hCG** (less than 35-53% in 48 hours) without a visible uterine pregnancy is highly concerning for **ectopic pregnancy**, making laparoscopy the gold standard for definitive diagnosis and treatment.*Administer intramuscular methotrexate*- Medical management with **methotrexate** typically requires a confirmed diagnosis of ectopic pregnancy or a high clinical suspicion where an **adnexal mass** is visible.- It is generally contraindicated if the diagnosis is uncertain and the patient is stable enough for a **laparoscopic evaluation** to find the exact location of the pregnancy.*Commence expectant management with weekly beta-hCG monitoring*- Expectant management is reserved for patients where **beta-hCG levels are falling** or are very low (<1,000 IU/L), suggesting a self-limiting miscarriage or resolving ectopic.- In this patient, the **rising beta-hCG** (even if suboptimal) indicates continuing trophoblastic activity, posing a high risk of rupture if left unmanaged.*Repeat transvaginal ultrasound in 48-72 hours*- Repeating ultrasound is indicated when the initial **beta-hCG is below the discriminatory zone** and the patient is asymptomatic.- Given the current level is **2,550 IU/L**, a viable intrauterine pregnancy would already be visible; further delay in surgical assessment increases the risk of **tubal rupture**.*Perform uterine evacuation for presumed miscarriage*- Uterine evacuation or **manual vacuum aspiration (MVA)** is used to confirm the absence of products of conception but carries the risk of delaying the diagnosis of an **extra-uterine pregnancy**.- This step might only be considered if a **non-viable intrauterine pregnancy** was suspected, but it does not address the primary concern of a potential ectopic pregnancy in the adnexa.
Question 90: A 34-year-old woman with polycystic ovary syndrome presents with a 15-month history of oligomenorrhoea with occasional very heavy bleeding episodes. She experiences a period approximately every 3-4 months, lasting 10-12 days with flooding and clots. BMI is 32 kg/m². She is not sexually active. Pelvic examination is normal. What is the underlying pathophysiological mechanism most likely responsible for her heavy menstrual bleeding?
- A. Anovulatory cycles causing prolonged unopposed oestrogen stimulation of endometrium (Correct Answer)
- B. Increased endometrial prostaglandin production causing impaired haemostasis
- C. Hyperinsulinaemia causing increased endometrial vascular permeability
- D. Elevated LH:FSH ratio causing deficient endometrial maturation
- E. Androgen excess causing endometrial hyperplasia and abnormal angiogenesis
Explanation: ***Anovulatory cycles causing prolonged unopposed oestrogen stimulation of endometrium*** - In **Polycystic Ovary Syndrome (PCOS)**, the absence of **ovulation** means no **corpus luteum** forms, leading to a persistent lack of **progesterone**. - This results in **unopposed oestrogen** stimulation, causing continuous **endometrial proliferation** and thickening. The lack of structured shedding leads to **irregular, heavy, and prolonged bleeding** when the unstable endometrium eventually sloughs. *Increased endometrial prostaglandin production causing impaired haemostasis* - This mechanism primarily explains heavy menstrual bleeding (HMB) in **ovulatory cycles**, where there's a prostaglandin imbalance (e.g., increased PGF2α/PGE2 ratio) leading to vasodilation and impaired platelet aggregation. - The patient's presentation of **oligomenorrhoea** and **irregular, heavy bleeding** strongly points to anovulation, not primarily a prostaglandin issue in regularly ovulating cycles. *Hyperinsulinaemia causing increased endometrial vascular permeability* - **Hyperinsulinaemia** is a common feature of PCOS and contributes to its metabolic and androgenic manifestations, but it is not the direct cause of heavy menstrual bleeding. - While insulin can influence various tissues, **increased endometrial vascular permeability** is not the primary pathophysiological mechanism for the heavy, irregular bleeding seen in anovulatory cycles. *Elevated LH:FSH ratio causing deficient endometrial maturation* - An elevated **LH:FSH ratio** is characteristic of PCOS and contributes to **follicular arrest** and anovulation. - However, it is the *consequence* of anovulation, specifically the **lack of progesterone**, that directly leads to the abnormal endometrial development and heavy bleeding, rather than the LH:FSH ratio itself causing deficient endometrial maturation in a direct sense. *Androgen excess causing endometrial hyperplasia and abnormal angiogenesis* - While **androgen excess** is a hallmark of PCOS, it primarily contributes to hirsutism, acne, and is often peripherally converted to oestrogen, which then acts on the endometrium. - High levels of **androgens** themselves often have an inhibitory effect on the endometrium; the bleeding is specifically due to the **progesterone deficiency** and resulting estrogen-driven hyperplasia rather than direct abnormal angiogenesis from androgens.
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