Impact of Uterine Fibroids on Vaginal Bleeding
Uterine fibroids are a leading cause of heavy and prolonged menstrual bleeding, affecting approximately 30% of patients with fibroids and representing one of the most common reasons for gynecological hospitalization. 1, 2
Mechanisms of Abnormal Bleeding
Fibroids cause heavy menstrual bleeding through multiple pathophysiologic mechanisms:
Vascular disruption: Fibroids create highly irregular vasculature with aberrant angiogenesis, including formation of venous lakes and venous trunks that block normal blood flow patterns 2, 3
Altered vasoconstrictor production: The endometrium overlying fibroids produces significantly reduced levels of vasoconstrictors, leading to increased menstrual blood loss 3
Increased angiogenic factors: Fibroids upregulate production of angiogenic factors such as basic fibroblast growth factor (bFGF), IGF-1, and IGF-2, while simultaneously reducing coagulation factor production 2, 3
Endometrial surface area expansion: Submucosal fibroids distort and enlarge the uterine cavity, increasing the total endometrial surface area available for bleeding 4
Clinical Consequences
The bleeding impact varies by fibroid location:
Submucosal fibroids (protruding into the uterine cavity) cause the most severe bleeding symptoms due to direct endometrial disruption and impaired decidualization response 4, 3
Intramural fibroids can cause heavy bleeding when they distort the endometrial cavity or reach significant size 4
Subserosal fibroids (projecting outward from the uterus) typically cause minimal to no bleeding symptoms 4
Secondary Effects
Heavy menstrual bleeding from fibroids leads to:
Anemia and fatigue: Chronic blood loss results in iron deficiency anemia requiring supplementation 5, 1
Chronic vaginal discharge: Prolonged bleeding episodes contribute to persistent discharge 1
Quality of life impairment: The combination of heavy bleeding, anemia, and associated symptoms significantly impacts daily functioning 4
Common Pitfall
A critical error is assuming all vaginal bleeding in patients with fibroids is fibroid-related. Endometrial thickening or abnormal bleeding patterns require endometrial biopsy to rule out hyperplasia or malignancy before attributing symptoms solely to fibroids 5, particularly in perimenopausal women or those with risk factors for endometrial pathology.