Background & Objectives: Despite of high family planning coverage in Ardabil province comparing to other provinces of country, the population growth rate is higher than other provinces in Ardabil that presents incorrect, discontinuous, and interrupted use of intrauterine devices (IUD). This research was carried out to investigate the continuation, and factors affecting to interrupted use of IUD in women referring to health centers of Ardabil city in 2004.

  Methods: The Subjects of this descriptive-analytic and historical cohort study were 301 women. Data were collected by a questionnaire and were analyzed by Kaplan-Meier Survival and Log-Rank tests through SPSS software.

  Results: Duration of continuous use of IUD was more than 18 months among 77.1 % of subjects. Average duration was higher in 20-25 years women (24.5 ± 1 months). The lowest duration of continuous use of IUD was observed among women with age higher then 25 years old (14.3 ± 3.4 months). There was a significant relationship between discontinuous use of IUD and volume of menstrual bleeding (p=0.005). The mean of continuation in the women with a lot of bleeding was 20.5 ± 1 while for the women with low bleeding was 22.4 ± 1.5. Type of referring to IUD control had meaningful correlation (p=0.03) with average duration of using this device. Mean time of continuation in women that referred occasionally was 23.8 ± 0.6. There was significant relation between complication and IUD interruption. The highest interruption time belonged to the women that declared the infection, wound and PID (mean 25.5 months) and the lowest interruption time was observed in the women with bleeding and spotting (mean 18 months).

  Conclusion: Continuation of using IUD in 87.4 % of women was less than 6 months, in 81.4% was from 6 to 12 months, and in 72.1 % was from 12 to18 months. The most common reason of discontinuation was medical factors and IUD caused complication. The most common complication was bleeding.