Does Endometriosis Cause Bleeding?
Yes, endometriosis commonly causes heavy menstrual bleeding, along with other bleeding-related symptoms such as prolonged menstrual periods. 1, 2
Types of Bleeding Associated with Endometriosis
Endometriosis causes bleeding through several mechanisms:
Heavy menstrual bleeding (menorrhagia) is a well-documented symptom of endometriosis, occurring when ectopic endometrial tissue responds to hormonal stimuli and undergoes cyclic bleeding at implantation sites. 1, 2, 3
Internal bleeding occurs within endometriotic lesions themselves—the ectopic endometrial tissue bleeds internally during menstruation, leading to inflammation, fibrosis, and the formation of blood-filled cysts (endometriomas), particularly in the ovaries. 4
Prolonged menstrual bleeding results from dysregulation of the menstrual cycle, with aberrant expression of matrix metalloproteinases and inflammatory mediators that prolong endometrial shedding. 5
Clinical Presentation
The bleeding manifestations of endometriosis include:
Cyclic heavy menstrual bleeding that corresponds with the menstrual cycle, as the ectopic endometrial tissue responds to the same hormonal fluctuations as normal endometrium. 1, 3
Dysmenorrhea (painful menstruation) typically accompanies the heavy bleeding, with pain often commencing before the onset of menstrual flow. 6, 1
The severity of bleeding symptoms does not necessarily correlate with the stage of disease—women with minimal endometriosis may experience significant bleeding while those with severe disease may have minimal symptoms. 1
Important Clinical Caveats
Adenomyosis frequently coexists with endometriosis and independently contributes to heavy menstrual bleeding, making it crucial to evaluate for both conditions when heavy bleeding is present. 7
Bladder endometriosis can present with urinary symptoms alongside heavy menstrual bleeding and should be considered in women with both urinary hesitancy and menstrual abnormalities. 2
The chronic inflammation at endometriotic lesion sites perpetuates bleeding through angiogenesis and increased vascular permeability. 3
Diagnostic Approach for Bleeding in Suspected Endometriosis
When evaluating a reproductive-age woman with heavy menstrual bleeding and suspected endometriosis:
Obtain transvaginal ultrasound as the initial imaging study to assess for structural causes including endometriomas, adenomyosis, and fibroids. 8
Consider MRI if ultrasound is inconclusive, as it provides superior visualization of deep infiltrating endometriosis and adenomyosis. 8
Laparoscopy with histologic confirmation remains the gold standard for definitive diagnosis, particularly for peritoneal endometriosis that may not be visible on imaging. 6