Length of the endometrial cavity and intrauterine contraceptive device expulsion

ObjectiveTo evaluate the correlation between endometrial cavity length and expulsion rate in acceptors of the TCu380A intrauterine device (IUD) or the levonorgestrel-releasing intrauterine system (LNG-IUS).MethodsThe study included 235 nulligravida and parous women who received a TCu380A IUD or LNG-IUS and who were observed for up to 1 year. The length of the uterine cavity was measured by uterine sounding and ultrasonography.ResultsThe endometrial cavity was shorter than 3.2 cm in 2 LNG-IUS users and at least 3.2 cm long in 87 LNG-IUS users, with expulsions occurring in 0 (0.0%) and 2 (2.3%) of these women, respectively (P > 0.999). Among the TCu380A IUD users, the endometrial cavity was shorter than 3.6 cm in 63 women and at least 3.6 cm long in 83 women, with expulsions occurring in 3 (4.8%) and 5 (6.0%) of these women, respectively (P > 0.999). The mean length of the endometrial cavity—evaluated via ultrasonography—among the 10 women whose devices were expelled was 3.9 ± 0.3 cm, compared with 3.9 ± 0.0 cm in those who retained their devices (P = 0.799).ConclusionThe present results do not support the hypothesis of an association between uterine length and risk of intrauterine contraceptive expulsion.