Contraceptive implant and LNG-IUD both reduce pelvic pain associated with endometriosis

Reference

Carvalho N, Margatho D, Cursino K, Benetti-Pinto CL, Bahamondes L. Control of endometriosis-associated pain with etonogestrel-releasing contraceptive implant and 52-mg levonorgestrel-releasing intrauterine system: randomized clinical trial. Fertil Steril 2018;110(6):1129-1136.

Synopsis

Progestins are commonly used treatments for endometriosis, while gonadotropin-releasing hormone (GnRH) analogues are arguably the reference standard to achieve regression of the disease. In a prior study (Tekin et al. Fertil Steril 2011;95:492-6), LNG-IUDs were shown to be equivalent to the GnRH analogue Zoladex for the treatment of chronic pelvic pain after laparoscopic treatment for endometriosis. In the current unmasked study 103 women with surgically and histologically confirmed endometriosis were included in a noninferiority trial of ENG to LNG-IUD. The women were aged 18 years to 45 years and had at least 6 months' history of noncyclic pelvic pain, dysmenorrhea, or both. Women were excluded if they had contraindication to either of the study methods according to World Health Organization criteria, had undergone surgical or hormonal treatment within the 2 months prior to enrollment, or wished to conceive within the next 12 months. Women were randomized to receive an ENG implant (Implanon NXT) as the experimental treatment or a 52-mg LNG-IUD (Mirena) as the control treatment. Insertions were performed within the first 5 days of the menstrual cycle. Pain was assessed using 10-cm visual analog scale, recorded daily and averaged on a monthly basis. Baseline pain was determined by daily readings during the month prior to device insertion. Study duration was 6 months; 82 women completing the study, with a similar number of drop-outs in each group. Noncyclic pain decreased similarly in both groups at study conclusion, from 7.6 +/- 1.7 cm to 2.0 +/- 2.4 in the ENG group and from 7.4 +/- 1.7 to 1.9 +/- 1.7 in the LNG-IUD group. Most of the pain reduction in both groups occurred within the first 2 months. Of note: Pain outcomes are highly susceptible to the placebo effect, and this study was neither placebo-controlled nor masked. An additional weakness to this study was that it was not analyzed by intention to treat.