Comparing levonorgestrel intrauterine system with hysteroscopic niche resection in women with postmenstrual spotting related to a niche in the uterine cesarean scar: a randomized, open-label, controlled trial

Abstract

Postmenstrual spotting and chronic pelvic pain after cesarean delivery are associated with the presence of niches. Levonorgestrel intrauterine system (52 mg) and hysteroscopic niche resection have been shown to relieve niche-related symptoms at 6 months after the intervention. This trial aimed to compare the effectiveness of 52-mg levonorgestrel intrauterine system with that of hysteroscopic niche resection in reducing niche-related postmenstrual spotting. This randomized, open-label, controlled trial was conducted at a medical center in Shanghai, China. Women with symptoms of postmenstrual spotting after cesarean delivery, with a niche depth of at least 2 mm and residual myometrium of at least 2.2 mm on magnetic resonance imaging, and no intention to conceive within the next year were randomly assigned to receive treatment with 52-mg levonorgestrel intrauterine system or hysteroscopic niche resection. The primary outcome was the reduction in postmenstrual spotting at 6 months after randomization, defined as the percentage of women with a reduction of at least 50% in spotting days relative to baseline. Efficacy and safety were assessed using intention-to-treat analysis. Between September 2019 and January 2022, 208 women were randomized into the levonorgestrel intrauterine system group (N=104) or the hysteroscopic niche resection group (N=104). At the 6-month follow-up, a 50% reduction in spotting had occurred in 78.4% (80/102) of women in the levonorgestrel intrauterine system group and in 73.1% (76/104) of women in the hysteroscopic niche resection group (relative risk, 1.07 [95% confidence interval, 0.92-1.25]; P=.370). Spotting decreased over time (Ptrend=.001), with a stronger reduction observed in the levonorgestrel intrauterine system group (P=.001). There was also a significant interaction between time and treatment (P=.007). From 9 months onward, a more significant reduction in spotting was observed in the levonorgestrel intrauterine system group than in the hysteroscopic niche resection group (9 months, 89.2% vs 72.1%; relative risk, 1.24 [95% confidence interval, 1.08-1.42]; 12 months, 90.2% vs 70.2%; relative risk, 1.29 [95% confidence interval, 1.12-1.48]). Moreover, compared with the hysteroscopic niche resection group, the levonorgestrel intrauterine system group had significantly fewer postmenstrual spotting days and total bleeding days from 6 months onward (all P<.001), and less pelvic pain from 3 months onward (all P<.010). No intervention-related complications were reported in any group. During follow-up, 11 (10.8%) women reported hormone-related side effects, and 2 women (2.0%) in the levonorgestrel intrauterine system group had spontaneous partial expulsion. Meanwhile, 3 unintended pregnancies were reported in the hysteroscopic niche resection group. In women with niche-related postmenstrual spotting, the levonorgestrel intrauterine system was not more effective than hysteroscopic niche resection in reducing the number of spotting days by at least 50% at 6 months. However, the levonorgestrel intrauterine system was superior in reducing spotting from 9 months onward, and it reduced the absolute number of spotting days from 6 months onward and pelvic pain from 3 months onward.