Description

• Dysfunctional uterine bleeding (DUB) is irregular bleeding (usually heavy, prolonged, or frequent); it is a diagnosis of exclusion after establishment of normal anatomy and the absence of other medical illnesses.
• Commonly associated with anovulation

Epidemiology

Adolescent and perimenopausal women are affected most often.

Incidence
5% of reproductive age women will see a doctor in any given year for DUB.

Prevalence
10–30% of reproductive age women have DUB.

Risk Factors

• Age >40
• Obesity
• Diabetes mellitus
• Nulliparity
• Early menarche or late menopause (>55 years)
• Hypertension
• Chronic anovulation or infertility
• Unopposed estrogen therapy
• History of breast cancer or endometrial hyperplasia
• Tamoxifen use
• Family history: Gynecologic, breast, or colon cancer

Genetics
Unclear, but can include inherited disorders of hemostasis

Pathophysiology

• Anovulation accounts for 90% of DUB:
  • Loss of cyclic endometrial stimulation
  • Elevated estrogen levels stimulate endometrial growth.
  • No organized progesterone withdrawal bleed
  • Endometrium eventually outgrows blood supply, breaks down, and sloughs from uterus.
• Adolescent DUB is usually due to an immature hypothalamic-pituitary-ovarian (HPO) axis that leads to anovulatory cycles.

Etiology

DUB can be broadly divided into anovulatory bleeding (usually irregular and unpredictable menses) or ovulatory bleeding (usually heavy regular menses) after pathologic causes of abnormal bleeding have been ruled out:

• Pregnancy: Ectopic pregnancy, threatened or incomplete abortion, or hydatidiform mole
• Reproductive pathology and structural disorders:
  • Uterus: Leiomyomas, endometritis, hyperplasia, polyps, trauma
  • Adnexa: Salpingitis, functional ovarian cysts
  • Cervix: Cervicitis, polyps, STIs, trauma
  • Vagina: Trauma, foreign body
  • Vulva: Lichen sclerosis, STIs
• Malignancy of the vagina, cervix, uterus, and ovaries
• Systemic diseases:
  • Inflammatory bowel disease
  • Hematologic disorders (e.g., Von Willebrand disease, thrombocytopenia)
  • Advanced or fulminant liver disease
  • Chronic renal disease
• Diseases causing anovulation:
  • Hyperthyroidism/Hypothyroidism
  • Adrenal disorders
  • Pituitary disease (prolactinoma)
  • Polycystic ovarian syndrome (PCOS)
  • Eating disorders
• Medications (iatrogenic causes):
  • Anticoagulants
  • Steroids
  • Tamoxifen
  • Hormonal medications: Intrauterine devices
  • SSRIs
  • Antipsychotic medications
• Other causes of abnormal uterine bleeding:
  • Excessive weight gain
  • Increased exercise
  • Stress