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Abnormal Uterine Bleeding (AUB)

Long Answer — Obstetrics & Gynaecology Examination

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Definition

• Cycle length: 24–38 days
• Duration of flow: 4–8 days
• Regular, cyclic, predictable bleeding

Older terms such as menorrhagia, metrorrhagia, menometrorrhagia, and dysfunctional uterine bleeding (DUB) are now largely replaced by the PALM-COEIN classification system.

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Epidemiology

• Affects 10–30% of women of reproductive age
• ~20% of cases occur in adolescents (postmenarchal) due to immaturity of the hypothalamic–pituitary–ovarian (HPO) axis
• ~50% occur in perimenopausal women related to incipient ovarian failure
• Approximately 75% of cases have no demonstrable organic cause and are associated with anovulation

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Nomenclature of Menstrual Disorders

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Classification: The PALM-COEIN System

PALM — Structural Causes

COEIN — Non-structural Causes

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Causes by Age Group

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Pathophysiology of Anovulatory AUB

1. No ovulation → No corpus luteum → No progesterone production
2. Endometrium proliferates under unopposed oestrogen
3. Endometrium becomes thick, fragile, and disorganized
4. Sheds irregularly → heavy, prolonged, unpredictable bleeding

• Oestrogen withdrawal bleeding: Drop in oestrogen levels causes irregular shedding
• Oestrogen breakthrough bleeding: Sustained, high oestrogen without progesterone leads to continuous proliferation and irregular shedding

• Hypothalamic/pituitary dysfunction (hyperprolactinaemia, prolactin-secreting adenomas)
• Polycystic Ovary Syndrome (PCOS) — most common in reproductive-age women
• Thyroid disorders (hypothyroidism, hyperthyroidism)
• Cushing's syndrome, Addison's disease
• Obesity, malnutrition, severe exercise, chronic systemic illness
• Perimenopausal ovarian failure

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Clinical Evaluation

History

• Onset, duration, frequency, and volume of bleeding (number of pads/tampons, clots)
• Menstrual calendar/charting
• Symptoms of anaemia (fatigue, dyspnoea, palpitations)
• Obstetric history, contraceptive use
• Symptoms suggesting coagulopathy: epistaxis, easy bruising, bleeding after dental extraction, family history
• Systemic symptoms: weight gain/loss, cold intolerance, galactorrhoea, hirsutism

Examination

• General: Signs of anaemia, thyroid enlargement, features of PCOS/endocrine disorders
• Abdominal: Uterine enlargement (fibroid/adenomyosis), adnexal mass
• Per speculum: Cervical lesions, polyps, cervicitis, vaginal pathology
• Bimanual: Uterine size, tenderness, adnexal pathology

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Investigation

Laboratory Tests (All cases)

• Urine/serum β-hCG — to rule out pregnancy
• Complete blood count — assess severity of anaemia
• Coagulation studies — PT, aPTT, platelet count, von Willebrand factor (if indicated)
• Thyroid function tests — TSH, T₄
• Serum prolactin
• Fasting blood glucose
• Cervical screening (Pap smear) if not up to date
• STI screening if indicated

When to Suspect a Bleeding Disorder (Berek & Novak's Gynecology)

• Heavy menstrual bleeding since menarche
• Family history of bleeding disorder
• Epistaxis in last year
• Bruising >2 cm without injury
• Prolonged bleeding after dental extraction
• Postpartum haemorrhage (especially delayed >24 hours)

Imaging

• Pelvic ultrasound (transvaginal): First-line imaging; evaluates endometrial thickness, fibroids, polyps, adenomyosis
• Sonohysterography (saline infusion sonography): Superior for intrauterine lesions (polyps, submucous fibroids)
• MRI: For clarifying adenomyosis, uterine anomalies, staging malignancy when ultrasound is inconclusive

Endometrial Biopsy

• All women ≥45 years with AUB (including intermenstrual bleeding)
• Women <45 years with:
  • Unopposed oestrogen exposure (obesity, PCOS)
  • Persistent AUB or AUB refractory to medical management
  • Elevated familial risk of endometrial/colorectal cancer

Hysteroscopy

• Gold standard for direct visualisation of the uterine cavity
• Diagnostic + therapeutic (polypectomy, targeted biopsy)
• Office hysteroscopy preferred; used when ultrasound findings are inconclusive or for investigation of persistent/unexplained AUB

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Management

Acute Heavy AUB (Haemodynamically Unstable)

• Urgent gynaecology consultation + admission
• IV fluid resuscitation ± blood transfusion if required
• IV conjugated oestrogens 25 mg every 4 hours (up to 3 doses) to stop acute bleeding
• Simultaneously start progestin (medroxyprogesterone acetate 5–10 mg orally for 10 days)
• If hormonal therapy fails → Dilation & Curettage (D&C) for immediate haemostasis
• Intrauterine Foley balloon tamponade (26F, 30 mL balloon) in selected cases

Medical Management

Hormonal Options

Non-Hormonal Options

Specific Conditions

• Anovulatory bleeding (PCOS): COCPs or cyclic progestins; induce ovulation if pregnancy desired
• Coagulopathy (von Willebrand): COCP, tranexamic acid, intranasal desmopressin (DDAVP)
• Hypothyroidism / hyperprolactinaemia: Treat the underlying cause (thyroxine, dopamine agonists)
• Endometrial hyperplasia without atypia: Progestins (systemic or LNG-IUS)
• Endometrial hyperplasia with atypia / carcinoma: Surgical (hysterectomy)

Surgical Management

D&C alone is not an effective means of controlling bleeding long-term and is not necessary before hysterectomy.

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Postmenopausal Bleeding — Special Consideration

• NOT classified under PALM-COEIN
• Any bleeding ≥12 months after last menstrual period must be considered abnormal and investigated thoroughly
• Most common cause: Endometrial atrophy
• Most important cause to exclude: Endometrial carcinoma
• Mandatory workup: Pelvic ultrasound (endometrial thickness) + endometrial biopsy

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Complications of Untreated AUB

• Chronic iron deficiency anaemia
• Infertility (from underlying anovulation/PCOS)
• Endometrial hyperplasia → carcinoma (from unopposed oestrogen)
• Psychological distress, reduced quality of life

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Prognosis

• Most cases of anovulatory AUB respond well to hormonal therapy
• Young women with postmenarchal anovulatory bleeding generally have a good prognosis for future regular ovulatory cycles and fertility
• Underlying conditions (PCOS, coagulopathies) require ongoing management
• Prognosis of AUB overall depends on the underlying cause and adequacy of treatment

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Summary Diagram

AUB
 ├── PALM (Structural)
 │    ├── Polyp
 │    ├── Adenomyosis
 │    ├── Leiomyoma (Submucosal / Other)
 │    └── Malignancy / Hyperplasia
 │
 └── COEIN (Non-structural)
      ├── Coagulopathy
      ├── Ovulatory Dysfunction (PCOS, thyroid, prolactin)
      ├── Endometrial
      ├── Iatrogenic
      └── Not yet classified

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