The width of the uterine cavity is narrower in patients with an embedded intrauterine device (IUD) compared to a normally positioned IUD.

OBJECTIVE The purpose of this study was to determine whether women with intrauterine devices (IUDs) embedded in the myometrium or cervix have a narrower fundal transverse endometrial diameter as seen on 3-dimensional (3D) sonography compared to women whose IUDs are in a normal location. METHODS A sonographer blinded to the study hypothesis retrospectively evaluated the 3D images and reconstructed coronal views of the uterine cavity in 172 consecutive women who had an IUD in the uterus. The width of the endometrial cavity at the fundus of the uterus was measured transversely on the rendered coronal sonogram using the calipers on a picture archiving and communications system. The measurements obtained from women who had nonembedded IUDs were compared to those with embedded IUDs. RESULTS Measurement of the width of the endometrial cavity at the fundus was successfully performed in 132 patients with nonembedded IUDs and 29 with embedded IUDs. The mean ± SD values of the fundal uterine cavity for the nonembedded and embedded IUDs were 32 ± 1.0 and 25 ± 0.8 mm, [corrected] respectively (P = .0003). CONCLUSIONS Patients with embedded IUDs have a smaller fundal endometrial cavity diameter compared to those with normally placed IUDs as documented using 3D rendering of the uterus. Whether preprocedural 3D sonography for women who are IUD candidates would be useful deserves further study.