Abnormal Uterine Bleeding: Symptoms, Causes & Treatment

Abnormal uterine bleeding (AUB) is defined as uterine bleeding that falls outside normal menstrual parameters: cycle frequency (<24 or >38 days), regularity (variation >7–9 days), duration (>8 days), or volume (PBAC score >100 or hemoglobin-depleting). The International Federation of Gynecology and Obstetrics (FIGO) updated classification system (PALM-COEIN) replaced older, vague terms ('dysfunctional uterine bleeding') with a structured etiological framework: structural causes (PALM: Polyp, Adenomyosis, Leiomyoma, Malignancy/hyperplasia) and non-structural causes (COEIN: Coagulopathy, Ovulatory dysfunction, Endometrial, Iatrogenic, Not yet classified).

AUB affects approximately 30% of reproductive-age women, representing one of the most common reasons for gynecological consultation. In premenopausal women, anovulatory AUB from PCOS, thyroid disease, or perimenopause is most common. In postmenopausal women, any uterine bleeding is considered abnormal and mandates endometrial evaluation to exclude malignancy — endometrial carcinoma occurs in approximately 10% of postmenopausal bleeding cases. Heavy menstrual bleeding (HMB, or menorrhagia) — historically defined as >80 mL blood loss per cycle — causes iron-deficiency anemia in 10–20% of affected women.

Management is individualized: medical therapy (hormonal or non-hormonal) for most premenopausal AUB; surgical evaluation (hysteroscopy, endometrial sampling) for suspected structural causes or malignancy; procedural interventions (endometrial ablation, myomectomy, hysterectomy) for structural lesions or refractory cases.

• Heavy menstrual bleeding (HMB): periods exceeding 7 days, soaking pads/tampons hourly for several consecutive hours, large clots — iron-deficiency anemia is common
• Intermenstrual bleeding: spotting or bleeding between cycles — suggests polyp, cervical pathology, or ovulatory dysfunction
• Postcoital bleeding: bleeding after intercourse — cervical pathology or vaginal atrophy
• Irregular menstrual cycles: <24 or >38 days, or high variability — suggests anovulation (PCOS, thyroid, perimenopause)
• Postmenopausal bleeding: any uterine bleeding >12 months after last period — mandates immediate evaluation for endometrial malignancy
• Anemia symptoms from chronic blood loss: fatigue, exertional dyspnea, palpitations, pallor

• Polyp: endometrial or cervical polyps — fragile epithelium bleeds easily; most common cause of intermenstrual bleeding
• Adenomyosis: endometrial glands within the myometrium — heavy, painful periods
• Leiomyoma (fibroids): submucosal and intramural fibroids distort the endometrial cavity — most common cause of HMB
• Malignancy/hyperplasia: endometrial carcinoma or hyperplasia (especially in postmenopausal bleeding, obesity, tamoxifen use, HNPCC)
• Coagulopathy: von Willebrand disease (most common inherited — evaluate in adolescents with HMB from menarche), thrombocytopenia, anticoagulant therapy
• Ovulatory dysfunction: PCOS (anovulation), hypothyroidism, hyperprolactinemia, perimenopause — irregular anovulatory cycles
• Iatrogenic: anticoagulants, antiplatelet agents, hormonal contraceptives, copper IUD, tamoxifen, antipsychotics (hyperprolactinemia)

Thorough menstrual history (cycle frequency, duration, volume using PBAC score). Physical examination: pelvic exam for cervical/vaginal abnormalities, uterine size and tenderness. Laboratory: CBC (anemia), coagulation studies (APTT, vWF — if HMB since menarche), TSH, prolactin, androgens (PCOS). Pregnancy test: rule out pregnancy-related bleeding (ectopic, miscarriage). Cervical cytology (Pap smear). Transvaginal ultrasound: endometrial thickness, fibroids, polyps. Endometrial biopsy: mandatory for postmenopausal bleeding, age >45, persistent AUB unresponsive to treatment, or risk factors for endometrial cancer (obesity, tamoxifen, HNPCC, diabetes). Hysteroscopy: direct visualization; gold standard for intracavitary pathology.

Medical therapy for non-structural AUB: tranexamic acid (antifibrinolytic — reduces blood loss 40–50%); NSAIDs (reduce prostaglandin-mediated bleeding 25–35%); combined OCP (regulates cycles); progestins (oral or injectable for anovulatory AUB); levonorgestrel-releasing IUD (LNG-IUS/Mirena) — reduces bleeding by 80–97%, most effective medical option. Structural causes: hysteroscopic polypectomy (polyps), myomectomy or uterine fibroid embolization (fibroids), treatment of adenomyosis with LNG-IUS or GnRH agonists. Endometrial ablation: for refractory HMB without desire for future fertility — outpatient, effective in 80% but not suitable if malignancy risk. Hysterectomy: definitive treatment for refractory cases. Malignancy/hyperplasia: surgical staging and oncological management.

• Iron-deficiency anemia from chronic blood loss — common and often undertreated
• Missed endometrial malignancy — postmenopausal bleeding is a red flag; delayed evaluation allows disease progression
• Quality-of-life impairment: work absenteeism, limitation of activities, relationship impact, depression

• Regular cervical screening (Pap smear) and endometrial evaluation in postmenopausal bleeding — early detection of malignancy
• Treatment of underlying PCOS, thyroid disease, and hyperprolactinemia normalizes ovulation and cycle regularity
• Progestogen protection of the endometrium in anovulatory women on estrogen (obesity, PCOS) prevents hyperplasia