Background: Consecutive use of the levonorgestrel-releasing intrauterine system (LNG-IUS) is increasing. However, little is known about factors that predict the bleeding during consecutive use. The objective of this study was to analyse the possible factors which may predict the bleeding pattern during the first year of use of a second LNG-IUS.
Methods: Fertile-aged women (n = 204) who had used their first LNG-IUS for over 4 years and who opted for a second LNG-IUS were recruited. Bleeding data were reported using 90-day reference periods (RPs) starting from the last 90 days of the first LNG-IUS use (baseline), until the end of the first year of the second LNG-IUS (RPs 1-4).
Results: Demographic factors such as age, parity, body mass index, indication of LNG-IUS use or smoking could not be identified as predictors for bleeding and spotting (B/S). Mean (+/-SD) number of B/S days was 8.9 (+/-9.1) at baseline. This increased slightly during RP1 and fell to 6.4 (+/-8.1) during RP4. Compared with the mean, women with uterine fibroids or a bleeding pattern of >9 days of spotting or any bleeding at RP1 had more B/S days during RP1-4. Although the number of B/S days decreased progressively from RP1 to RP4 in the group with a bleeding pattern of >9 days of spotting or any bleeding at baseline, such a phenomenon was not observed for women with fibroids. The difference for the change in B/S days between women with and without fibroids was statistically significant at RP3 and RP4. A high degree (91.7%) of satisfaction with the bleeding pattern was observed, with amenorrhoeic women being most satisfied.
Conclusions: Uterine B/S is reduced during consecutive use of the LNG-IUS. Women with uterine fibroids or any bleeding at baseline continued to have more B/S than other women.