Background: In view of current controversies regarding the need for new, shorter intrauterine devices (IUDs) that would reduce expulsion rates in nulligravida, endometrial cavity length was measured in women of different parities using uterine sounding and ultrasonography.
Study design: A cross-sectional descriptive study was performed including 570 women of 17-52 years of age, 260 of whom were nulligravida and 310 parous.
Results: The difference in mean length between measurements taken by uterine sounding and ultrasonography was 0.28 cm. Mean endometrial cavity length was 3.84+/-0.03 cm (mean+/-S.E.M.) in nulligravida and 4.25+/-0.03 cm in parous women according to uterine sounding (p<.001) and 3.70+/-0.03 cm and 3.84+/-0.03 cm, respectively, according to ultrasonography (p=.006).
Conclusions: By either technique, mean length of the endometrial cavity was >3.6 cm, the length of the most common IUDs, the TCu380A and the levonorgestrel-releasing intrauterine system. Therefore, the issue appears controversial for developing new, shorter IUDs, since current models fit most women, including nulligravida, albeit one third of the women of our sample showed endometrial length shorter than 3.2 cm.