Effect of intracervical anesthesia on pain associated with the insertion of the levonorgestrel-releasing intrauterine system in women without previous vaginal delivery: a RCT

Abstract

Is the pain associated with levonorgestrel-releasing intrauterine system (LNG-IUS) insertion reduced by intracervical anesthesia in women without previous vaginal birth? Intracervical anesthesia was not associated with reduced pain in women without previous vaginal birth. The pain associated with the insertion of intrauterine contraceptives (IUCs) is a limiting factor for the use of these contraceptives by some women. No prophylactic pharmacological intervention has proven efficacy in relieving pain during or after the insertion of IUCs. However, previous studies included women with previous vaginal delivery, and injectable intracervical anesthesia was not evaluated in any of these studies. This was a randomized, open, parallel-group clinical trial that evaluated 100 women without previous vaginal delivery who wished to use the LNG-IUS for the first time. These women were evaluated immediately after LNG-IUS insertion and then 2 h and 6 h later. The 100 women were randomized into two groups: (i) use of a non-steroidal anti-inflammatory drug (NSAID) (ibuprofen, 400 mg) 1 h prior to LNG-IUS insertion; or (ii) 2% lidocaine intracervical injection 5 min prior to LNG-IUS insertion. The women were evaluated immediately after LNG-IUS insertion and then 2 h and 6 h after insertion. Two pain scales were used (the visual analogue scale and the facial pain scale) in addition to assessing the ease of insertion (as rated by the provider) and the level of discomfort during the procedure (as rated by the patient). Multivariate logistic regression was performed to analyze the predictors associated with moderate/severe pain. The pain and discomfort associated with LNG-IUS insertion, and the ease of insertion of the LNG-IUS did not differ between the groups. Nulliparity was more associated with moderate/severe pain [adjusted odds ratio (OR): 3.1 (95% confidence interval (CI): 1.3-7.80]. Injectable intracervical anesthesia use reduced the risk of moderate/severe pain by 40% [adjusted OR: 0.6 (95% CI: 0.2-1.4)]. The difference between the mean pain score in the intracervical anesthesia group and the NSAID group was <10%; thus, the effect size of the intervention was not significant. Intracervical anesthesia was compared with an oral medication in this study. Intracervical injection of a saline solution or even a dry needling as the placebo for a double-blind study could be a more adequate control; however, this approach was not a protocol approved by the institutional review board. Considering that the majority of the insertions were easy (>80% in both groups), the results may not be extrapolated to difficult insertions with moderate/severe pain where local anesthesia may have a role. The findings can be generalized to most insertions in nulliparous women or in those without a previous vaginal delivery. There is currently no evidence to recommend the routine use of prophylactic intracervical anesthesia prior to LNG-IUS insertion; there is no evidence that this treatment reduces insertion-related pain. RAF and CSV give occasional lectures for Bayer Healthcare. This study received funding from the National Institute of Hormones and Women's Health, National Council for Scientific and Technological Development (CNPq). NCT02155166.