Description

• HMB is a form of abnormal uterine bleeding (AUB) and is defined as a volume of menstrual blood loss that interferes with the patient’s physical, social, emotional, and/or material quality of life.
• Based on current terminology, menorrhagia is regular bleeding that is heavy or prolonged with cyclic (ovulatory) menses.
• It is based on the patient’s perspective as increased volume of menstrual flow, regardless of the duration, frequency, or regularity.
• This volume as defined by clinical trials is >80 mL of blood lost per cycle (one third of the patients documented); however, self-assessment can be inaccurate. Indirect assessment has been developed for better measurement.
• There is consensus to abandon the use of the term menorrhagia as it is found to be confusing and/or poorly defined.

Epidemiology

• In the United States, AUB accounts for 20–30% of all gynecologic visits and results in more than half of hysterectomies performed annually for benign uterine disorders.
• The prevalence varies with age, most commonly occurring at menarche and perimenopause.
• HMB is linked to decreased quality of life and increased health care costs, with significant morbidity due to anemia.

Etiology and Pathophysiology

• Any derangement in the structure of the uterus, in the clotting pathways, or disruption of the hypothalamic-pituitary-ovarian axis can cause HMB.
• The pathophysiology of HMB is outlined with reference to the International Federation of Gynecology and Obstetrics (FIGO) PALM-COEIN classification system of AUB (1). More research needs to be done to elaborate the many causes of this condition.
• HMB can be caused by structural issues such as (PALM acronym):
  • Polyp (AUB-P)
  • Adenomyosis (AUB-A)
  • Leiomyoma (AUB-L)
  • Malignancy/hyperplasia (AUB-M)
• Excessive estrogen stimulation likely causes polyps, which are abnormal outgrowths of hypertrophied endometrial tissue. It does not demonstrate the normal cyclical changes of normal endometrium causing irregular and intermenstrual HMB.
• Adenomyosis may cause HMB by affecting normal myometrial contraction, but the exact cause is unknown.
• Leiomyomas are common benign myometrial neoplasms thought to form as a result of chromosomal abnormalities and grow in response to estrogen and progesterone. The exact cause for HMB lacks sufficient evidence to support the many proposed theories.
• Excess estrogen can promote endometrial hyperplasia and insufficient reduction in progesterone to promote shedding may underlay heavy bleeding.
• It can also be caused by nonstructural causes which include (COEIN acronym):
  • Coagulopathy (AUB-C)
  • Ovulatory (AUB-O)
  • Endometrial (AUB-E)
  • Iatrogenic (AUB-I)
  • Not yet classified (AUB-N)
• Ovulatory dysfunction is associated with a thick stratum functionalis caused by excessive estrogen stimulation of the endometrium. Endometrial shedding tends to be noncyclical with irregular bleeding noted.
• HMB can also be classified as ovulatory or anovulatory bleeding.
• Conditions in not otherwise classified category include pelvic inflammatory disease (PID), chronic liver disease, and cervicitis
• Rare etiologies include arteriovenous malformations, myometrial hyperplasia, and endometritis

Pediatric Considerations
Due to immaturity of the hypothalamic-pituitary-ovarian axis, adolescents are at risk for irregular and HMB. Of note, adolescents with heavy bleeding should be evaluated for possible bleeding disorders, especially von Willebrand disease and qualitative platelet dysfunction.

Risk Factors

Obesity

General Prevention

• Combined oral contraceptives may prevent HMB particularly when progesterone is dominant. Lower estrogen doses result in less menstrual bleeding.
• Progesterone-only contraceptives may reduce overall blood loss but often result in irregular bleeding.

History

• It is important to obtain a proper understanding of the patient’s bleeding episode and to ask questions focused on PALM-COEIN etiologies to determine the patient’s cause of abnormal bleeding.
• Recent or current pregnancy
• Menstrual history and bleeding patterns: menarche, LMP, menses frequency, regularity, duration, the volume flow, intermenstrual and postcoital bleeding. To determine the quantity of blood loss, pads changed every 2 to 3 hours represents at least 80 mL of blood loss.
• Sexual history: Evaluate for PID, STI, pain, fever, discharge.
• History of obstetric or gynecologic surgery, contraceptive use, IUD, medication use, chronic medical conditions
• Initial screening for underlying disorder of hemostasis:
  • HMB since menarche; two or more of family history of bleeding symptoms, frequent gum bleeding, epistaxis 1 to 2 times per month, or bruising 1 to 2 times per month; one of the following: bleeding associated with dental work, surgery-related bleeding, or postpartum hemorrhage
  • Positive screen comprises any of the above categories and warrants further testing and hematology referral.
  • Anovulatory bleeding is noted to be irregular, unpredictable, and the patient lacks typical ovulatory symptoms such as midcycle pain or premenstrual symptoms.

Physical Exam

• Assess hemodynamic stability, and if unstable (tachycardia, hypotension, positive orthostatic), need to be stabilized in the emergency department before proceeding with additional evaluation
• The goal of PE is to look for signs of systemic illness, such as fever, ecchymoses, an enlarged thyroid gland, or evidence of hyperandrogenism such as hirsutism or acne. Acanthosis nigricans may be seen in polycystic ovary syndrome (PCOS), galactorrhea can suggest hyperprolactinemia.
• A complete pelvic examination should be performed, inspecting the vulva, urethra, vagina, anus, and perineum. Note signs of trauma like lacerations. It is also prudent to note any hemorrhoids as a possible source of bleeding.
• Bimanual exam is done to feel for uterine or cervical abnormalities or enlargement. Pelvic and adnexal masses would also be palpated during this exam.
• Cervical cancer screening

Differential Diagnosis

• Normal menses
• Complication of pregnancy
• Other sources of bleeding (e.g., cervical, vaginal, gastrointestinal)

Diagnostic Tests & Interpretation

Medication

Issues for Referral

Refer to gynecology if a primary care physician is uncomfortable placing an IUD, performing endometrial sampling, if there is persistent bleeding despite treatment, or malignancy is suspected. Depending on etiology, refer to hematology, oncology, or interventional radiology.

Additional Therapies

• Iron replacement therapy PO (preferred) or IV (if unable to tolerate oral) for anemia
• MRI-guided focused ultrasound (MgFUS) had been approved by the FDA for the treatment of uterine fibroids and has been used with success in decreasing bleeding in patients with adenomyosis.

Surgery/Other Procedures

• Intrauterine tamponade, uterine artery embolization, endometrial ablation, dilation and curettage can be considered in the setting of acute severe bleeding.
• Surgical procedures are directed to the specific identified pathology.
  • Endometrial and cervical polyps—polypectomy
  • Adenomyosis—hysterectomy
  • Leiomyoma—for women who do not desire fertility laparoscopic radiofrequency ablation, uterine artery embolization or hysterectomy can be performed. For women who desire fertility, myomectomy is preferred.
  • Malignancy—hysterectomy with or without adjuvant chemotherapy and radiotherapy
• Conservative surgery (i.e., myomectomy, endometrial ablation, or uterine artery embolization) is more effective for controlling bleeding symptoms at 1 and 2 years than oral medications or the levonorgestrel-releasing IUD, but by 5 years, there is no difference in long-term results or patient satisfaction.
• Hysterectomy, the definitive treatment, may be necessary for failure of medical management or presence of another indication such as malignancy.

Patient Education

Worldwide, many women do not report AUB to their health care providers. It is important to have an open discussion on menstruation, and patient should be educated on any pertinent lifestyle changes, treatment options, and when to seek emergency care.

Prognosis

Favorable but vastly dependent on etiology. The main goal is to rule out malignancy and improve patient’s quality of life.

Complications

Anemia, infertility, endometrial cancer

Additional Reading

• Centers for Disease Control and Prevention. About bleeding disorders in women. https://www.cdc.gov/female-blood-disorders/about/index.html. Accessed September 8, 2025.
• Centers for Disease Control and Prevention. Materials about signs and symptoms. https://www.cdc.gov/female-blood-disorders/communication-resources/signs-a.... Accessed September 8, 2025.
• Cheong Y, Cameron IT, Critchley HOD. Abnormal uterine bleeding. Br Med Bull. 2019;131(1):119.  [PMID:31220225]
• Committee on Practice Bulletins—Gynecology. Practice bulletin no. 128: diagnosis of abnormal uterine bleeding in reproductive-aged women. Obstet Gynecol. 2012;120(1):197–206.  [PMID:22914421]
• Hill S, Shetty MK. Abnormal uterine bleeding in reproductive age women: role of imaging in the diagnosis and management. Semin Ultrasound CT MR. 2023;44(6):511–518.  [PMID:37832698]

ICD-10

• N92.0 Excessive and frequent menstruation with regular cycle
• N92.3 Ovulation bleeding
• N92.2 Excessive menstruation at puberty
• N92.1 Excessive and frequent menstruation with irregular cycle

SNOMED

• 386692008 Menorrhagia (finding)
• 386804004 Disorder of menstruation (disorder)
• 266602005 Puberty bleeding (finding)
• 266601003 excessive and frequent menstruation (finding)