Endometriosis on C-Section Scar and Menstrual Bleeding
No, endometriosis implanted in a cesarean-section scar does not cause increased menstrual bleeding. Cesarean scar endometriosis (CSSE) is a localized extra-pelvic condition that presents with cyclical pain and swelling at the scar site, not systemic menstrual bleeding changes.
Clinical Presentation of Cesarean Scar Endometriosis
CSSE manifests as a distinct entity with highly characteristic symptoms:
- Cyclical pain at the incision site that recurs with menstruation is the hallmark symptom 1, 2, 3
- Palpable tender mass in the cesarean scar location, typically appearing months to years after surgery 2, 3, 4
- Brownish discharge from the lesion during menstruation may occur in superficial cutaneous cases 2
- Localized swelling at the scar site that worsens cyclically 4
The symptoms are confined to the scar tissue itself and do not affect the endometrial cavity or overall menstrual flow 1, 2.
Pathophysiology and Location
CSSE develops through direct implantation of endometrial cells along the surgical route during cesarean delivery:
- Endometrial tissue implants anywhere along the cesarean section path, including skin, subcutaneous tissue, abdominal wall muscles, or the uterine scar itself 1
- The implanted tissue proliferates under hormonal stimulation but remains localized to the scar area 2, 3
- Synchronous intra-abdominal endometriosis is not required for CSSE to develop 1
- The condition is extra-pelvic and does not involve the endometrial cavity where menstrual bleeding originates 1
Why Menstrual Bleeding Is Not Affected
The key distinction is anatomical separation:
- CSSE represents ectopic endometrial tissue outside the uterine cavity, functioning independently from the intrauterine endometrium that generates menstrual flow 1, 2
- The scar endometriosis undergoes cyclical changes (swelling, pain) but does not contribute to or increase menstrual blood volume 2, 3
- Menstrual bleeding originates from shedding of the intrauterine endometrium, which is anatomically and functionally separate from scar implants 1
Important Clinical Pitfall
Do not confuse CSSE with intrauterine pathology that could cause abnormal bleeding:
- If a patient with prior cesarean section presents with increased menstrual bleeding, investigate for intrauterine causes such as retained products of conception, subinvolution of placental bed, endometritis, or uterine scar dehiscence with intrauterine involvement 5
- CSSE should be suspected when there is a painful soft-tissue mass along the cesarean scar with cyclical symptoms, not when the primary complaint is heavy menstrual bleeding 1, 4
- Cesarean scar dehiscence with fluid collections can occur postpartum but represents structural defects, not endometriosis, and would not cause ongoing increased menstrual bleeding in subsequent cycles 6
Diagnostic Approach When CSSE Is Suspected
When evaluating a mass at a cesarean scar:
- MRI with T1 fat-saturated sequences is the most sensitive imaging method, showing hyperintense hemorrhagic foci that strongly support the diagnosis 1
- Ultrasound findings are non-specific but useful for ruling out other differentials and guiding biopsy 1
- Histopathology provides definitive diagnosis, showing endometrial glands and stroma in the scar tissue 2, 3, 4
- Wide surgical excision is the mainstay of treatment to prevent recurrence 2, 3, 7
If increased menstrual bleeding is the presenting complaint in a patient with prior cesarean section, the diagnostic workup should focus on intrauterine pathology, not scar endometriosis 5.