Characteristics of uterine contractility during menses in women with mild to moderate endometriosis.

OBJECTIVE

To establish the role of uterine contractions in retrograde menstruation with subsequent abdominal implantation of endometrial tissue.

DESIGN

Controlled prospective study.

SETTING

University hospital-based study.

PATIENT(S): Infertile women with (n = 22) and without (n = 22) endometriosis.

MAIN OUTCOME MEASURE(S): Frequency, amplitude, and basal pressure tone of uterine contractions; correlation of contractions with retrograde bleeding and presence of viable endometrial cells; and dysmenorrhea before and 3 and 24 months after surgery.

RESULT(S): Compared with controls, patients with endometriosis had uterine contractions with higher frequency (22.73 +/- 5.66 osc/10 min vs. 11.09 +/- 3.26 osc/10 min), amplitude (20.83 +/- 3.94 mm Hg vs. 6.77 +/- 2.83 mm Hg), and basal pressure tone (50.14 +/- 16.30 mm Hg vs. 24.68 +/- 6.14 mm Hg). Dysmenorrhea was scored as 4.09 +/- 1.44 in patients with endometriosis and 0.86 +/- 1.42 in controls. Retrograde bleeding was found in 73% of patients with endometriosis vs. 9% of controls, and only 45% of patients with endometriosis had viable endometrial cells in the cul-de-sac.

CONCLUSION(S): Endometriosis may result from abnormal myometrial contractility through tubal transportation, dissemination, and implantation of endometrial viable cells into the abdomen.