CLINICAL PRINTABLE
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A one-page Abnormal Uterine Bleeding clinical reference is on the way.
1 · Recognition / Alarm Features
- AUB definitions: heavy menstrual bleeding (HMB) — >80 mL per cycle or bleeding lasting >7 days; intermenstrual bleeding (IMB) — bleeding between regular menses; irregular menstrual bleeding — cycle length <24 or >38 days; postcoital bleeding; postmenopausal bleeding (PMB) — any vaginal bleeding >12 months after last menstrual period.
- First step: rule out pregnancy (urine or serum beta-hCG). Ectopic pregnancy, miscarriage, and gestational trophoblastic disease all present with abnormal bleeding. Do not proceed with AUB workup without excluding pregnancy.
- PALM-COEIN classification: Structural causes (PALM) — Polyp, Adenomyosis, Leiomyoma (fibroid), Malignancy/hyperplasia. Nonstructural causes (COEIN) — Coagulopathy, Ovulatory dysfunction, Endometrial, Iatrogenic, Not yet classified.
- Postmenopausal bleeding: endometrial cancer until proven otherwise. Transvaginal ultrasound (endometrial stripe >4 mm requires biopsy). Endometrial biopsy is the diagnostic standard. Refer to gynecology.
- Coagulopathy as a cause of AUB: von Willebrand disease is the most common inherited bleeding disorder causing HMB. Screen with ISTH-BAT (bleeding assessment tool) or ask: heavy bleeding since menarche, postpartum hemorrhage, surgical bleeding, dental bleeding. If positive, check vWF antigen, vWF activity, and factor VIII.
2 · Differential / Secondary Causes
Uterine fibroids (leiomyoma)
Most common benign uterine tumor. Heavy, prolonged menstrual bleeding, pelvic pressure, urinary frequency. Submucosal fibroids cause the most significant bleeding. Pelvic ultrasound for diagnosis. Treatment: hormonal (levonorgestrel IUD, combined OCP, progestins), GnRH agonists, or surgical (myomectomy, hysterectomy, uterine fibroid embolization).
Endometrial polyp
Intermenstrual bleeding, postcoital bleeding, or heavy menstrual bleeding. Transvaginal ultrasound (echogenic endometrial lesion). Hysteroscopy with polypectomy is diagnostic and therapeutic. Risk of malignancy is low (<1%) but increases with age and postmenopausal status.
Ovulatory dysfunction (AUB-O)
Irregular, unpredictable bleeding due to anovulation. Common in perimenopause, PCOS, thyroid disease, hyperprolactinemia, and hypothalamic dysfunction. Unopposed estrogen leads to endometrial proliferation and irregular shedding. Check TSH, prolactin, and consider PCOS evaluation.
Endometrial cancer / hyperplasia
Risk factors: obesity, diabetes, hypertension, nulliparity, late menopause, tamoxifen use, Lynch syndrome. Postmenopausal bleeding or abnormal bleeding in women >45 with risk factors. Endometrial biopsy. Refer to gynecologic oncology.
Iatrogenic (AUB-I)
Anticoagulants (warfarin, DOACs), antiplatelet agents, hormonal contraceptives (breakthrough bleeding), SSRIs (platelet dysfunction), copper IUD (increased menstrual flow). Review the medication list. Adjust or switch medications when possible.
3 · Treatment Pathway
Acute heavy bleeding — stabilization
High-dose estrogen (conjugated estrogen 25 mg IV every 4–6 hours for up to 24 hours) for acute severe bleeding. Oral high-dose combined OCP (monophasic 35 mcg ethinyl estradiol) TID for 7 days, then taper. Tranexamic acid (antifibrinolytic) 1.3 g PO TID for 5 days during heavy bleeding. IV access, CBC, coagulation studies, type and screen for severe hemorrhage.
Levonorgestrel IUD (Mirena) — first-line for HMB
Reduces menstrual blood loss by 70–90%. First-line for heavy menstrual bleeding without structural cause. Also provides contraception. Effective for AUB-O, AUB-E, and AUB-I. Can be used in women with fibroids (submucosal fibroids may prevent insertion or expulsion).
Combined oral contraceptives (COCs)
Reduce menstrual blood loss by 40–50%. Regulate cycle. Appropriate for women desiring contraception. Contraindicated in: smokers >35 years, hypertension, migraine with aura, history of VTE, cardiovascular disease.
Progestins
Oral progestins (norethindrone, medroxyprogesterone acetate): for anovulatory AUB. Cyclic progestins (days 14–25 of cycle) regulate irregular bleeding. Continuous progestins for endometrial protection in women with unopposed estrogen. Depot medroxyprogesterone acetate (DMPA): reduces or eliminates menstrual bleeding.
Surgical options
Endometrial ablation: destroys endometrial lining. Effective for HMB without structural cause. Not appropriate for women desiring future fertility. Hysteroscopic polypectomy or myomectomy for structural causes. Hysterectomy: definitive treatment for refractory HMB. Uterine fibroid embolization (UFE): minimally invasive, preserves uterus.
4 · Expected Response
- Levonorgestrel IUD: 70–90% reduction in menstrual blood loss. Amenorrhea in 20–30% of users at 1 year. Irregular spotting common in first 3–6 months.
- Combined OCP: 40–50% reduction in menstrual blood loss. Regular, predictable cycles. Full effect within 1–3 cycles.
- Endometrial ablation: 80–90% of women have significantly reduced or absent menstrual bleeding. 20–30% achieve amenorrhea. Not effective for submucosal fibroids.
5 · Escalation
- Postmenopausal bleeding: endometrial cancer until proven otherwise. Transvaginal ultrasound and endometrial biopsy. Refer to gynecology.
- Hemodynamic instability from acute heavy bleeding: IV access, IV fluids, blood transfusion if needed, IV estrogen, urgent gynecology consultation.
- Suspected endometrial cancer or hyperplasia (risk factors + abnormal bleeding): endometrial biopsy, refer to gynecologic oncology.
- Suspected coagulopathy (bleeding since menarche, family history, positive bleeding assessment tool): hematology referral for von Willebrand disease evaluation.
Apply It · Change One Detail
APPLY IT
A 34-year-old woman presents with heavy menstrual bleeding (soaking a pad every hour for 2 days, passing clots). Pregnancy test is negative. Pelvic ultrasound shows a 3 cm submucosal fibroid. She does not desire future fertility. Discuss options: levonorgestrel IUD (may be difficult to place with submucosal fibroid), combined OCP, tranexamic acid during heavy days, or hysteroscopic myomectomy. Refer to gynecology for hysteroscopy — submucosal fibroids are best managed surgically.
CHANGE ONE DETAIL
Change one detail — a 55-year-old postmenopausal woman presents with vaginal bleeding. She has been postmenopausal for 3 years. Any vaginal bleeding after 12 months of amenorrhea is postmenopausal bleeding — endometrial cancer until proven otherwise. Order transvaginal ultrasound (endometrial stripe >4 mm requires biopsy). Refer to gynecology for endometrial biopsy. Do not attribute to atrophy without ruling out malignancy.
Bottom Line
Always rule out pregnancy first. Postmenopausal bleeding is endometrial cancer until proven otherwise — transvaginal ultrasound and endometrial biopsy. Use the PALM-COEIN framework to classify AUB before selecting treatment.
EVIDENCE & REFERENCES
- Munro MG, et al. FIGO classification system (PALM-COEIN) for causes of abnormal uterine bleeding in nongravid women of reproductive age. Int J Gynaecol Obstet. 2011;113(1):3-13. doi:10.1016/j.ijgo.2010.11.011
- American College of Obstetricians and Gynecologists. ACOG Practice Bulletin No. 128: Diagnosis of Abnormal Uterine Bleeding in Reproductive-Aged Women. Obstet Gynecol. 2012;120(1):197-206. doi:10.1097/AOG.0b013e318262e320
- Matteson KA, et al. Nonsurgical management of heavy menstrual bleeding: a systematic review. Obstet Gynecol. 2013;121(3):632-643. doi:10.1097/AOG.0b013e3182839e0e