Duration of use of a levonorgestrel IUS amongst nulliparous and adolescent women

Background: Intrauterine devices are cost-effective if used for 2 or more years. Early discontinuation may lead to reduced cost-effectiveness of this method and unintended pregnancy if other contraceptives are not used. This study sought to examine rates and reasons for discontinuation of IUS use in adolescents versus older women and nulliparous versus parous women, as these groups may be more likely to discontinue use.

Study design: Retrospective cohort study of women receiving a levonorgestrel IUS between June 2005 and April 2008 was conducted. Medical records were reviewed for all visits following placement of the IUS; rates and reasons for IUS discontinuation were calculated and categorized. Data were examined under two scenarios: (1) assuming that all women not seen for follow-up continued IUS use and (2) only including women with follow-up visits. Cox regression was used to control for age, parity, race and marital status in comparing rates of IUS discontinuation and expulsion in nulliparous versus parous women and adolescents versus older women.

Results: Of the 828 women included in this analysis, 104 (12.6%) were nulliparous, and 131 (15.8%) were ≤20 years of age. Nulliparous women were not more likely than parous women to have expelled their IUS [hazard ratio (95% confidence interval), 1.40 (0.57, 3.43)]. Adolescent women were more likely to experience expulsion than older women, although this did not reach statistical significance [hazard ratio, 1.49 (0.76, 2.92)]. When we looked at reasons for IUS removal, we found that nulliparous women were not more likely than parous women to have their IUS removed because of dissatisfaction with the contraceptive method (6.7% vs. 11.5%, p=.15) or desire to become pregnant (1.9% vs. 2.6%, p=.50). Similarly, adolescents were not more likely than older women to have their IUS removed because of dissatisfaction with the contraceptive method (10.7% vs. 10.9%, p=.94) or desire to become pregnant (3.1% vs. 2.4%, p=.43).

Conclusions: Adolescents and nulliparous women are not more likely to prematurely discontinue use of their IUS than adult or parous women.