Objective: To describe the propagation direction of the subendometrial myometrial contractile wave in menstrual phase sonographically assessed in patients with and without endometriosis.
Design: Prospective study.
Setting: Patients and normal volunteers in a university hospital.
Patients: Sixteen women with (study group) and 21 without (control group) endometriosis.
Interventions: Patients were examined by transvaginal sonography (midsaggital plane of the uterus) and recorded on videotape for a 5-minute period.
Main outcome measure: Direction of propagation of contraction waves.
Results: The endometriosis group showed a predominant retrograde pattern whereas the control group showed a normal antegrade.
Conclusion: This abnormal cervix-to-fundus myometrial activity could well increase the amount of peritoneal shedding of endometrial menstrual debris, increasing the probabilities of its heterotopic implantation.