Bernaschek G, Endler M, Beck A
Geburtshilfe Frauenheilkd. 1981 Aug;41(8):566-9. doi: 10.1055/s-2008-1037278.
The correct position of an IUD in the uterine cavity is essential for the effectiveness of the method. Ultrasound examination of the thickness of the anterior and posterior wall of the uterus were carried out and their relation to a correct position of the IUD calculated. It was found that the position of the IUD is correct, if the distance between fundus and the cranial end of the IUD does not exceed the thickness of the uterine wall by more than one-third; i. e. in all 4/3 of the thickness. The correlation between the ultrasound results of length, version and flexion of the uterus and complaints and side-effects like bleeding and pain are discussed, especially if the IUD is not in correct position.
宫内节育器（IUD）在子宫腔内的正确位置对于该避孕方法的有效性至关重要。对子宫前后壁厚度进行了超声检查，并计算了其与IUD正确位置的关系。结果发现，如果子宫底部与IUD头端之间的距离不超过子宫壁厚度的三分之一以上，即不超过子宫壁厚度的4/3，则IUD位置正确。文中还讨论了子宫长度、倾度和屈度的超声检查结果与诸如出血和疼痛等主诉及副作用之间的相关性，尤其是当IUD位置不正确时。
