Risk Factors for Levonorgestrel-releasing Intrauterine System (LNG-IUS) Expulsion among Chinese Women Treated for Menstrual Disorders: Retrospective Cohort Study in a Regional Hospital

Abstract

Objective: To investigate the risk factors for levonorgestrel-releasing intrauterine system (LNG-IUS) expulsion among Chinese women treated for menstrual disorders.
Methods: This was a retrospective cohort study in patients who had had LNG-IUS insertion, and involved comparison of characteristics in women in whom the system had or had not been expelled. The patients who were reviewed had LNG-IUS insertions carried out between 1 January 2001 and 31 December 2009 at the Princess Margaret Hospital, Hong Kong. The parameters studied were: age at insertion, number of previous vaginal births, number of previous Caesarean sections, the lowest haemoglobin level recorded in the last 2 years, previous pelvic sonographic examination, presence of fibroids, presence of adenomyosis, and the sounded uterine length at insertion.
Results: Expulsion of LNG-IUS was noted in 29% (23/80) of cases, in 52% (12/23) of whom expulsion had occurred within the first 6 months. We observed that pre-insertion sonographic pelvic examination (p < 0.05) was associated with a higher LNG-IUS expulsion rate. For all other factors, there was no statistically significant association with expulsion.
Conclusion: No significant isolated risk factors were encountered for LNG-IUS expulsion. Pre-insertion sonographic pelvic examination probably implied presence of significant uterine pathologies. A low haemoglobin level reflecting menorrhagia correlated with the expulsion rate. In view of treatment effectiveness, LNG-IUS should be offered for the treatment of menstrual disorders when indicated. The unexpectedly high LNG-IUS expulsion rate noted in this study reinforces the need for patient counselling regarding this possibility.