Medline ® Abstract for Reference 53

OBJECTIVE: To establish the continuation rates of the levonorgestrel intrauterine system (LNG IUS) and symptoms associated with its premature removal.

SAMPLE AND SETTING: All women in Finland who had a LNG IUS inserted between April 1990 and December 1993 and whose doctor had filled in and returned a form at the insertion visit. This study population consists of 46% of all the LNG IUSs sold in Finland between 1990 and 1993.

DESIGN: A questionnaire on reproductive and contraceptive history, gynaecological problems and symptoms experienced during the use of the LNG IUS was sent to 23,885 LNG IUS users. A total of 17,914 questionnaires were returned (response rate 75%). The results cover experience from 58,600 woman years. A log-rank-test was used to test differences in continuation rates. Multivariate analyse were performed using Cox's proportional hazard model.

RESULTS: The LNG IUS was prematurely removed from 5175 women. The one, two, three, four and five year continuation rates were 93%, 87%, 81%, 75% and 65%, respectively. The symptoms during the use of the LNG IUS most strongly associated with its premature removal were excessive bleeding and spotting, and infections and pain. The risk of premature removal was markedly lower among women who had occasional or total absence of menstruation. Premature removal was less likely in the oldest age group.

CONCLUSIONS: The continuation rate of the LNG IUS compares favourably with other long-acting contraceptive systems. Totally or occasionally absent menstruation was strongly associated with prolonged continuation.