Gynaecology

Recognising Bleeding Disorders: Foundations of Abnormal and Ectopic Bleeding

A 32-year-old woman presents with heavy periods requiring pad changes every hour, describing clots "the size of golf balls." Meanwhile, in the emergency department, a 28-year-old with 6 weeks amenorrhoea reports unilateral pelvic pain and light vaginal bleeding. These scenarios represent two critical gynaecological presentations-abnormal uterine bleeding and ectopic pregnancy -that demand systematic evaluation and timely intervention. Understanding their classifications, epidemiology, and diagnostic frameworks forms the cornerstone of competent gynaecological practice.

Abnormal Uterine Bleeding (AUB) Classification:

• PALM-COEIN system (FIGO 2011) stratifies causes into structural and non-structural:
  • Structural (PALM): Polyp, Adenomyosis, Leiomyoma, Malignancy
  • Non-structural (COEIN): Coagulopathy, Ovulatory dysfunction, Endometrial, Iatrogenic, Not classified
• Heavy menstrual bleeding (HMB): Excessive blood loss (>80ml/cycle) interfering with quality of life
  • Affects 25% of women of reproductive age
  • Accounts for 20% of gynaecology referrals in UK primary care
• Intermenstrual bleeding (IMB): Bleeding between regular cycles
• Postcoital bleeding (PCB): Bleeding after sexual intercourse-requires cervical assessment

Ectopic Pregnancy Essentials:

• Definition: Pregnancy implanted outside the uterine cavity
  • 95% tubal (ampulla most common site)
  • Rare sites: ovarian (3%), cervical, caesarean scar, abdominal
• Epidemiology:
  • Incidence 11 per 1,000 pregnancies in UK
  • Leading cause of maternal death in first trimester (6% of maternal deaths)
  • Recurrence risk 10-15% after one ectopic

📌 Mnemonic for Ectopic Risk Factors: PIPES
PID, IUD, Previous ectopic, Endometriosis, Surgery (tubal)

2 - Pathophysiological Mechanisms: Why Bleeding Occurs

The mechanisms underlying abnormal bleeding diverge fundamentally between structural uterine pathology and ectopic implantation. In abnormal uterine bleeding , disrupted endometrial haemostasis results from either anatomical distortion (fibroids creating increased surface area, adenomyosis disrupting myometrial contractility) or molecular dysregulation (increased prostaglandin E2/prostacyclin ratio, impaired vasoconstriction). Anovulatory cycles-common in PCOS and perimenopause-produce unopposed oestrogen stimulation, causing irregular endometrial proliferation without progesterone-mediated stabilisation, leading to unpredictable breakthrough bleeding.

AUB Mechanistic Pathways:

• Structural causes:
  • Fibroids: Distort endometrial vasculature, increase surface area (submucosal worst)
  • Adenomyosis: Ectopic endometrial glands in myometrium → impaired uterine contractility
  • Polyps: Localised endometrial overgrowth with fragile vasculature
• Coagulopathy (13% of HMB):
  • Von Willebrand disease most common (1% population prevalence)
  • Platelet dysfunction, factor deficiencies
• Endometrial dysfunction:
  • Altered prostaglandin ratios (↑ PGE2:PGF2α)
  • Increased fibrinolysis (elevated tissue plasminogen activator)
  • Impaired vasoconstriction

Ectopic Pregnancy Pathophysiology:

In ectopic pregnancy , impaired tubal transport allows blastocyst implantation in the fallopian tube. Risk factors-previous PID causing tubal scarring, endometriosis creating inflammatory milieu, tubal surgery disrupting ciliary function-all compromise the tube's ability to propel the embryo uterine-ward. The trophoblast invades the tubal wall, eroding blood vessels and causing bleeding into the peritoneal cavity. Unlike the muscular uterus, the thin-walled tube cannot accommodate growing gestational tissue, leading to rupture typically at 6-8 weeks gestation when β-hCG reaches 3,000-5,000 IU/L.

Loading diagram…

3 - Clinical Assessment: History, Examination, and Investigations

A 45-year-old presents with "flooding" periods lasting 9 days, passing clots, and requiring time off work. You quantify impact using a structured history, examine for structural causes, and order targeted investigations per NICE NG88 guidance. Meanwhile, a 26-year-old with positive pregnancy test and cramping requires urgent assessment for potential ectopic pregnancy , where clinical gestalt combined with serial β-hCG and transvaginal ultrasound determines management pathway.

History-Taking Priorities:

• AUB assessment:
  • Quantify bleeding: Pictorial Blood Assessment Chart (PBAC >100 = HMB)
  • Pattern: Regular/irregular, cycle length, intermenstrual/postcoital bleeding
  • Impact: Anaemia symptoms (fatigue, palpitations), quality of life, fertility plans
  • Risk factors: Obesity (anovulation), anticoagulation, PCOS, thyroid disease
• Ectopic pregnancy red flags:
  • Triad: Amenorrhoea (6-8 weeks) + pelvic pain (unilateral) + vaginal bleeding
  • Rupture indicators: Sudden severe pain, shoulder tip pain (diaphragmatic irritation), dizziness/syncope

Examination Findings:

• AUB: Abdominal masses (fibroids), bimanual examination (enlarged/tender uterus), speculum (exclude cervical pathology)
• Ectopic: Abdominal tenderness, cervical motion tenderness, adnexal mass (50%), peritonism if ruptured

Investigation Algorithm (NICE NG88 & NG126):

• AUB first-line:
  • Full blood count: Hb <120 g/L indicates significant blood loss
  • Ferritin: <15 μg/L confirms iron deficiency
  • Coagulation screen if HMB since menarche or family history
  • Pelvic USS: First-line imaging for structural causes
• Ectopic pregnancy pathway:
  • Serum β-hCG: Discriminatory zone 1,500 IU/L (transvaginal USS should visualise intrauterine pregnancy)
  • Transvaginal USS: Intrauterine gestational sac (confirms IUP), adnexal mass, free fluid
  • Serial β-hCG (48h): Normal IUP rises >63%, ectopic typically <50% increase

Loading diagram…

4 - Differential Diagnosis: Distinguishing Bleeding Causes

Separating benign from life-threatening bleeding requires systematic analysis. A 34-year-old with irregular bleeding and negative pregnancy test differs fundamentally from one with positive test and pain-the latter demands urgent ectopic exclusion . Similarly, distinguishing ovulatory HMB (regular cycles, structural causes) from anovulatory bleeding (irregular, endocrine dysfunction) guides targeted management for abnormal uterine bleeding .

Key Discriminators:

• Pregnancy status: β-hCG positive = ectopic/miscarriage/molar until proven otherwise
• Cycle regularity:
  • Regular cycles (21-35 days) → structural causes (fibroids, polyps, adenomyosis)
  • Irregular cycles → anovulation (PCOS, thyroid, hyperprolactinaemia)
• Age stratification:
  • <20 years: Coagulopathy (13% of adolescent HMB)
  • 30-40 years: Fibroids, adenomyosis

  • 45 years: Endometrial cancer (2% of PMB)-requires urgent investigation

Common Diagnostic Pitfalls:

• Assuming negative urine pregnancy test excludes ectopic: False negatives occur with low β-hCG
• Missing coagulopathy: Ask about bruising, dental bleeding, family history
• Overlooking cervical pathology: Always visualise cervix with speculum
• Attributing all irregular bleeding to PCOS: Exclude endometrial hyperplasia/cancer

5 - Evidence-Based Management: Medical, Surgical, and Conservative Options

NICE NG88 advocates a stepwise approach to abnormal uterine bleeding , prioritising medical management unless structural pathology mandates surgery. First-line treatment-levonorgestrel intrauterine system (LNG-IUS)-reduces menstrual blood loss by 94% at 12 months, superior to all oral therapies. For ectopic pregnancy , NICE NG126 stratifies management by haemodynamic stability, β-hCG level, and patient preference, balancing tubal preservation against treatment success.

AUB Medical Management:

• First-line: LNG-IUS (Mirena®)
  • Dose: 52mg levonorgestrel, releases 20μg/day
  • Efficacy: 94% reduction in menstrual blood loss
  • Contraindications: Current breast cancer, distorted uterine cavity
• Tranexamic acid: 1g TDS days 1-4 of menses (39% reduction)
• Mefenamic acid: 500mg TDS days 1-4 (20-25% reduction)
• Combined oral contraceptive: Regulates cycle, reduces flow (43% reduction)

AUB Surgical Options:

• Endometrial ablation: For completed childbearing, normal cavity
  • Success: 80% satisfaction at 5 years
  • 24% require further surgery
• Hysterectomy: Definitive treatment
  • Laparoscopic preferred (shorter recovery, fewer complications)
  • Mortality risk 0.38 per 1,000

Ectopic Pregnancy Management:

• Expectant management (selected cases):
  • Criteria: β-hCG <1,000 IU/L, falling, minimal symptoms, reliable patient
  • Success: 69% resolve without intervention
• Medical: Methotrexate
  • Criteria: β-hCG <1,500 IU/L, unruptured, no fetal heartbeat, mass <35mm
  • Dose: 50mg/m² IM single dose (or multi-dose protocol)
  • Success: 88% (single dose), 93% (multi-dose)
  • Monitoring: β-hCG days 4 and 7 (expect 15% drop); repeat if <15% fall
  • Contraindications: Breastfeeding, immunodeficiency, renal/hepatic impairment
• Surgical: Laparoscopy
  • Salpingectomy: Removes affected tube (preferred if damaged tube, recurrent ectopic)
  • Salpingotomy: Preserves tube (if contralateral tube damaged, desire fertility)
  • Emergency laparotomy: If haemodynamically unstable

Loading diagram…

6 - Complex Scenarios: Special Populations and Advanced Cases

Real-world patients present nuanced challenges. A 38-year-old with HMB and concurrent anticoagulation for prosthetic heart valve requires coordinated cardiology input before considering surgical management . Similarly, a woman with recurrent ectopic pregnancy and single remaining tube faces difficult decisions balancing fertility preservation against treatment success . These scenarios demand synthesis of clinical evidence, patient values, and multidisciplinary expertise.

Challenging AUB Cases:

• Anticoagulation + HMB:
  • Tranexamic acid safe with warfarin/DOACs (no thrombotic risk increase)
  • LNG-IUS preferred (local effect, minimal systemic absorption)
  • Avoid NSAIDs if on antiplatelet therapy
• Adolescent HMB:
  • 13% have underlying coagulopathy-screen with PT, APTT, vWF antigen/activity
  • Combined OCP first-line (regulates cycle, reduces flow)
  • Avoid LNG-IUS (insertion difficult, poor tolerance)
• Perimenopausal bleeding:
  • Exclude malignancy: Endometrial biopsy if >45 years with persistent IMB
  • LNG-IUS prevents endometrial hyperplasia during HRT
• Failed medical management:
  • Consider GnRH analogues (3-6 months pre-surgery to reduce fibroid size)
  • Uterine artery embolisation: 85% satisfaction, preserves fertility potential

Complex Ectopic Scenarios:

• Pregnancy of unknown location (PUL):
  • β-hCG <1,500, no USS findings
  • Serial β-hCG protocol: 48h intervals until location confirmed or resolved
  • 10-15% ultimately ectopic
• Caesarean scar ectopic:
  • Rare (1:2,000) but increasing with rising CS rates
  • High rupture risk-requires specialist management (methotrexate + local injection or surgery)
• Cornual/interstitial ectopic:
  • Implantation in uterine horn
  • Later rupture (12-16 weeks), catastrophic haemorrhage
  • Requires laparotomy (not laparoscopy)-mortality 2-2.5%

High Yield Summary

Key Take-Aways:

• HMB affects 25% of women; LNG-IUS is first-line medical management (94% reduction in menstrual blood loss)
• Ectopic pregnancy occurs in 1.1% of pregnancies; discriminatory β-hCG threshold is 1,500 IU/L for transvaginal USS
• PALM-COEIN classification systematically categorises AUB causes into structural and non-structural
• Methotrexate criteria for ectopic: β-hCG <1,500, unruptured, mass <35mm, no fetal heartbeat-88% success rate
• Serial β-hCG in normal IUP rises >63% in 48 hours; slower rise suggests ectopic or failing pregnancy
• Endometrial sampling mandatory for women >45 years with persistent intermenstrual bleeding (exclude cancer)
• Ruptured ectopic presents with triad: sudden severe pain, shoulder tip pain (diaphragmatic irritation), haemodynamic instability

Essential Gynaecology Numbers:

Key Principles:

• Always exclude pregnancy in reproductive-age women with bleeding-urine test insufficient if symptoms suggest ectopic
• Structured history trumps investigations: PBAC score, impact on quality of life, and fertility plans guide AUB management
• Haemodynamic stability determines urgency: Unstable ectopic requires immediate laparotomy regardless of investigations
• Medical management first for AUB unless contraindications (distorted cavity, malignancy) or patient preference for surgery
• Serial monitoring essential in pregnancy of unknown location: 10-15% ultimately ectopic, requiring vigilant β-hCG tracking

Quick Reference: