Is 2-dimensional transvaginal ultrasonography necessary 6 weeks after insertion of the levonorgestrel 52-mg intrauterine device?

BACKGROUND: In Dutch practice, gynecologists are used to assessing the position of the LNG-IUD by performing a two-dimensional transvaginal ultrasonography (TVUS) directly after insertion and do not routinely invite patients for another consultation 4-12 weeks after insertion. There is no consensus whether a TVUS six weeks after insertion is routinely needed. OBJECTIVE: This study aimed to assess the incidence of malposition using 2-dimensional transvaginal ultrasonography during routine investigation 6 weeks after insertion. In addition, we investigated the relationship between malposition of the levonorgestrel 52-mg intrauterine device and unfavorable bleeding patterns and pelvic pain. STUDY DESIGN: We performed a large prospective cohort study. Patients seeking a levonorgestrel 52-mg intrauterine device were eligible for inclusion. Transvaginal ultrasonography was performed to check position of the levonorgestrel 52-mg intrauterine device immediately after insertion and 6 weeks later. Patients filled in questionnaires about bleeding pattern and pelvic pain 6 weeks after insertion. RESULTS: From March 2015 to December 2016, we enrolled 500 patients. Data from the transvaginal ultrasonography assessment 6 weeks after insertion were available for 448 patients, and complete data (transvaginal ultrasonography and questionnaire data) were available for 363 patients (72.6%). Malposition rate was 6.3% (28/448 patients). Malposition was seen in 15 of 198 patients (7.6%) with unfavorable bleeding and/or pelvic pain and in 3 of 165 patients (1.8%) with favorable bleeding patterns and no pelvic pain (P=.03). Malposition was seen in 14 of 186 patients (7.5%) with an unfavorable bleeding pattern and in 4 of 177 patients (2.3%) with favorable bleeding patterns (P=.008). Malposition was seen in 5 of 50 patients (10%) with pelvic pain and in 13 of 313 patients (4.2%) without pelvic pain (P=.08). CONCLUSION: The malposition rate of the levonorgestrel 52-mg intrauterine device observed using transvaginal ultrasonography 6 weeks after insertion was 6.3%. If patients have no complaints of unfavorable bleeding and/or pelvic pain, the risk for malposition is low (1.8%) and a routine transvaginal ultrasonography is not necessary. However, if patients experience unfavorable bleeding, a transvaginal ultrasonography should be considered to exclude malposition, because the effect of malposition on contraceptive effectiveness is unsure. Future research should focus on cost-benefit analysis.