RCT to evaluate the influence of adjuvant medical treatment of peritoneal endometriosis on the outcome of IVF.

STUDY QUESTION Does a 3-month adjuvant hormonal treatment of mild peritoneal endometriosis after laparoscopic surgery influence the outcome of IVF stimulation in terms of number of mature oocytes obtained per cycle? SUMMARY ANSWER Complementary medical treatment of mild peritoneal endometriosis does not influence the number of oocytes per treatment cycle. WHAT IS KNOWN ALREADY Endometriosis is a disease known to be related to infertility. However, the influence of superficial endometriosis-and its treatment-is still a matter of debate. STUDY DESIGN, SIZE, DURATION A prospective controlled, randomized, open label trial was performed between February 2012 and March 2014 and embryological and clinical outcomes were measured. Patients with laparoscopically diagnosed peritoneal endometriosis (n= 120) were treated by laser surgery after which they were sequentially randomized by computer-generated allocation to one of the two groups. The primary outcome of the trial was the number of Metaphase II (MII) oocytes. Sample size was chosen to detect a difference of two MII oocytes with a power of 80%. The control group (Group B) received the classical long protocol IVF stimulation, whereas the research group (Group A) had an additional pituitary suppression, of 3 months using a long-acting GnRH agonist, prior to IVF. PARTICIPANTS/ MATERIALS, SETTING, METHODS A total of 120 patients were included in the study, 61 of them in the study group and 59 patients in the control group. One patient of the control group was lost to follow up leading to 58 evaluable patients. MAIN RESULTS AND THE ROLE OF CHANCE There was no difference in terms of the number of MII oocytes obtained per cycle: 8.2 in both groups (difference in MII between A and B: 0.07 [-1.89; 2.04] 95% confidence interval (CI)). Pregnancy rate did not differ, being 39.3% for Group A (24 out of 61 patients) versus 39.7% for Group B (23 out of 58 patients) (95% CI around difference in pregnancy rate between A and B: -0.31% [-17.96%; 17.86%]). However, a significantly (P = 0.025) lower dose of FSH (2561 IU for Group A and 2303 IU for Group B, 95% CI around difference in FSH between B and A: -258.6 IU [-483.4 IU; -33.8 IU]) and a significantly (P = 0.004) shorter stimulation period (Group A 12.3 days and Group B 11.3 days, 95% CI around difference in stimulation period between B and A: -1.03 days [-1.73 days; -0.33 days]) were needed to reach adequate follicle maturation in the control group. LIMITATIONS, REASON FOR CAUTION The validity of this study is limited to mild peritoneal endometriosis, and does not apply to ovarian endometriosis, which is also commonly seen in infertility patients. WIDER IMPLICATIONS OF THE FINDINGS There is no indication for complementary medical treatment of peritoneal endometriosis in terms of IVF outcome. On the contrary, stimulation takes longer and requires a higher amount of medication. STUDY FUNDING/COMPETING INTERESTS There was no external funding for this clinical trial in the IVF Center, AZ Jan Palfijn, Ghent. There are no competing interests to declare. TRIAL REGISTRATION NUMBER EudraCT nr: 2012-000784-25. TRIAL REGISTRATION DATE First registration on 29 February 2012 and re-entered on 23 August 2012, NCT01682642 (due to a change of staff). DATE OF FIRST PATIENT'S ENROLLMENT 8 March 2012.