The use of different doses levonorgestrel-releasing intrauterine system (LNG-IUS): real-world data from a multicenter Italian study

Purpose: Current research fails to adequately inform about the differential use of available levonorgestrel-releasing intrauterine systems (LNG-IUSs) in real life. Aim of our study was to compare the characteristics, satisfaction, continuation rates, and adverse effects between users of the high-dose LNG-IUS (52 mg) and of the low dose LNG-IUS (13.5 mg and 19.5 mg).

Materials and methods: A prospective cohort study was performed in two Services for Family Planning in normal menstruating women with the inclusion of all new prescriptions of LNG-IUS for contraception. Women were followed for a mean of 9.1 ± 2.6 months after placement.

Results: 109 women (mean age of 39.8 ± 8.7 years old) were included, 69.7% using a high dose LNG-IUS and 30.3% using a low dose LNG-IUS. Women with a low dose LNG-IUS were significantly younger, thinner, more nulliparous, with fewer vaginal deliveries and C-sections, with a lower menstrual flow length and with more previous use of short-acting reversible contraceptives (p < 0.05). LNG-IUS continuation was similar and very high at the last follow-up: 100 vs. 94.7% in the low and high dose LNG-IUS groups, respectively (p = 0.18). Satisfaction with treatment at the end of the study was similar between different LNG-IUS doses (p = 0.85), with 78.9% being satisfied/very satisfied. Bleeding patterns were significantly different between the two LNG-IUS doses (p < 0.0001). Diagnosis of dysfunctional cysts was more frequent in women with high dose compared to low dose LNG-IUS (22.2 vs. 12.1%), albeit not significantly.

Conclusions: We have shown a clear differential use of available LNG-IUS in clinical practice, both as baseline characteristics and as different outcomes, primarily for bleeding patterns. However, all these systems were associated with a very high rate of satisfaction and continuation.