Vaginal Parturition Decreases Recurrence of Endometriosis

The incidence of endometriosis among women with dysmenorrhea is 40% to 60% and those with subfertility is 20% to 30%. After surgical treatment of endometriosis, recurrence is common, with an estimated rate of 4.6% to 31%. The primary concern in management of endometriosis is to limit or prevent recurrence. The primary aim of this study was to investigate the role of vaginal parturition in reducing the recurrence rates of endometriosis and dysmenorrhea. The secondary aim was to assess the role of uterine internal ostium (IOS) enlargement in the recurrence of endometriosis and dysmenorrhea after vaginal parturition. The study subjects were 345 infertile, nulliparous women with stage II to IV endometriosis and dysmenorrhea. Occurrence and recurrence of endometriosis were detected and treated with laparoscopy. Data were obtained prospectively and analyzed retrospectively. Dysmenorrhea was evaluated using a visual analog scale to estimate pain severity. The measurement of uterine IOS was performed using ultrasound. The primary study outcome measures were the determination of the extent of dysmenorrhea, rates of occurrence and recurrence of endometriosis, the degree of uterine IOS enlargement, and the relation of these measures to parity and mode of parturition. Recurrence of dysmenorrhea after delivery was significantly higher among nulliparous women as compared to women with vaginal parturition. The recurrence rate of endometriosis was significantly lower in women who had vaginal parturition than in those who underwent cesarean delivery. A significant enlargement of the uterine IOS was found after vaginal parturition but not cesarean section. IOS enlargement was associated with a reduction in both the risk of dysmenorrhea and recurrence of endometriosis. These data show that vaginal parturition has a protective role in the recurrence of endometriosis.