Menstrual cups are increasingly used as alternatives to tampons, collecting menstrual fluid with very few side-effects, as previously reported in the literature.
We present the case of a 47-year-old woman with pain in her right flank and an entrapped bladder caused by an incorrectly placed menstrual cup, complicated by acute unilateral hydronephrosis. We describe the computed tomography features that made it possible to make a correct diagnosis. We conducted a literature review in order to be able to list the reported side-effects of the use of menstrual cups.
Given their common use today, it is important that physicians become familiar with menstrual cups and are capable of recognizing cup misplacement to avoid complications such as hydronephrosis.