Factors affecting the spontaneous expulsion of the levonorgestrel-releasing intrauterine system.
OBJECTIVE
To estimate the incidence of, and identify risk factors for, spontaneous expulsion of the levonorgestrel-releasing intrauterine system (LNG-IUS).


METHODS
Pre-insertion characteristics for 481 women who received the LNG-IUS at a single institution in the Republic of Korea between 2003 and 2011 were analyzed retrospectively. The median duration of follow-up was 13.4 months. Kaplan-Meier plots were constructed to estimate the time to occurrence of spontaneous expulsion in multiple subgroups.


RESULTS
The overall crude incidence of spontaneous LNG-IUS expulsion was 9.6%. The cumulative incidence was 7.9%, 9.1%, and 9.6% at 1, 2, and 3 years, respectively. It was significantly higher in women with adenomyosis (9.1%, 10.6%, and 11.1%) or uterine leiomyoma (14.5%, 15.8%, and 15.8%) than in those with a normal uterus (3.6%, 4.1%, and 4.6%) (P=0.008). Women with heavy menstrual bleeding (11.0%, 12.7%, and 13.4%), dysmenorrhea (8.1%, 9.0%, and 10.0%), or pre-insertion receipt of gonadotropin-releasing hormone agonists (13.3%, 16.0%, and 17.3%) also had higher cumulative incidences than those without these conditions (P<0.05). Most (84.5%) women with a spontaneous expulsion chose to discontinue the device.


CONCLUSIONS
Clinicians need to be aware of the risk factors for spontaneous LNG-IUS expulsion because this can lead to a discontinuation of its use.
Department of Obstetrics and Gynecology, Seoul National University Hospital, Seoul, Republic of Korea.
Jina
J
Youm
Department of Obstetrics and Gynecology, Seoul National University Hospital, Seoul, Republic of Korea.
Hyun Ju
HJ
Lee
Department of Obstetrics and Gynecology, Seoul National University Bundang Hospital, Seongnam, Republic of Korea.
Seul Ki
SK
Kim
Department of Obstetrics and Gynecology, Seoul National University Hospital, Seoul, Republic of Korea.
Hoon
H
Kim
Department of Obstetrics and Gynecology, Seoul National University Bundang Hospital, Seongnam, Republic of Korea; Department of Obstetrics and Gynecology, Seoul National University College of Medicine, Seoul, Republic of Korea. Electronic address: blasto@snubh.org.
Byung Chul
BC
Jee
D000293:Adolescent; D000328:Adult; D003271:Contraceptive Agents, Female / Q000008:administration & dosage*; D005260:Female; D006801:Humans; D015994:Incidence; D007433:Intrauterine Device Expulsion; D007436:Intrauterine Devices, Medicated; D053208:Kaplan-Meier Estimate; D016912:Levonorgestrel / Q000008:administration & dosage*; D008875:Middle Aged; D012307:Risk Factors; D055815:Young Adult
D003271:Contraceptive Agents, Female; D016912:Levonorgestrel
Adenomyosis; Heavy menstrual bleeding; Intrauterine device expulsion; Levonorgestrel; Risk factors; Uterine leiomyoma