The value of transvaginal ultrasound to monitor the position of an intrauterine device after insertion. A technology assessment study.

BACKGROUND The intrauterine device (IUD) is an effective contraceptive method. The contraceptive power as well as the side-effects of IUD are thought to relate to the position of the IUD in the uterine cavity. We assessed the accuracy of clinical evaluation of IUD position. METHODS A prospective comparative study was performed. The clinical evaluation was compared with the TVU measurement of IUD position both immediately after insertion and 6 weeks after insertion. The primary outcome measures were the positive and negative predictive values (PPV and NPV) of the clinical evaluation of IUD position. RESULTS 195 women were included consecutively, 181 women (92.8%) were available for follow-up. The PPV and NPV of clinical evaluation of IUD position immediately after insertion were respectively 0.60 (95% CI: 0.39-0.81) and 0.98 (95% CI: 0.96-1.0). The prevalence of an abnormally positioned IUD was 7.7% (95% CI: 3.9-11.4). The PPV and NPV of the clinical evaluation at follow-up were respectively 0.54 (95% CI: 0.26-0.81) and 1.0 (95% CI: 0.98-1.0). The prevalence of abnormal position was 4.0% (95% CI: 1.7-7.1). CONCLUSION Clinical evaluation is an excellent test for the evaluation of the position of an IUD and routine TVU is not indicated for this purpose.