The incidence and characteristics of uterine bleeding during postoperative GnRH agonist treatment combined with estrogen-progestogen add-back therapy in endometriosis patients of reproductive age.

To evaluate the incidence and characteristics of uterine bleeding during postoperative gonadotropin-releasing hormone agonist (GnRHa) treatment combined with the lowest effective dose of estrogen-progestogen add-back therapy in Chinese women of reproductive age with endometriosis. Seventy Chinese women aged 18 to 50 years with stage III or IV endometriosis and treated with postoperative GnRHa after conservative surgery for endometriosis were eligible for this study. Patients were randomly divided into two equal groups, G and A. Group G (n = 35) received three 28-day cycles of postoperative GnRHa treatment by subcutaneous injection (goserelin, 3.6 mg). Group A (n = 35) received the same GnRHa treatment in addition to daily estradiol valerate (0.5 mg) and dydrogesterone (5 mg) add-back therapy. Serum E2 and FSH levels were assessed at the end of each treatment cycle, as well as incidence and patterns of uterine bleeding. After the last GnRHa treatment cycle, endometrial thickness was evaluated by ultrasonography and the recovery of menstruation was recorded. Uterine bleeding incidence was above 90% in both groups during the first treatment cycle (group G: 90.6%; group A: 93.8%), but decreased markedly in the second treatment cycle (group G: 15.6%; group A: 21.9%), and continued to decline until the end of the third treatment cycle (group G: 6.3%; group A: 12.5%). For each cycle, the incidence of uterine bleeding in group A was slightly but not statistically higher. Irregular spotting was the most common uterine bleeding pattern observed in each of the three treatment cycle. The addition of estrogen and progestogen therapy to a postoperative GnRHa regimen does not lead to an increase in the duration or amount of treatment-induced uterine bleeding.