Transmural migration and perforation of a levonorgestrel intrauterine system: a case report and review of the literature

INTRODUCTION: Uterine perforation is an uncommon yet well-known complication of copper intrauterine devices and the levonorgestrel intrauterine system (IUS). While initial extrauterine placement at the time of insertion is felt to be the cause of perforation in most cases, some hypothesize that delayed transmural migration and subsequent perforation can occur with slightly malpositioned or even properly placed devices. CASE: A 46-year-old female had a 52-mg levonorgestrel IUS inserted for menstrual management and contraception. We arranged a follow-up ultrasound as the uterus was enlarged on bimanual examination and the cavity sounded to 11cm. This ultrasound was completed 6days after insertion and reported the IUS to be in the "upper uterine cavity". Over time, transmural displacement and perforation of the horizontal arms of the device occurred. Computed tomography scans performed over 2years for nongynecologic indications document this gradual migration. A retrospective review of initial ultrasound images showed no evidence of uterine defect, embedment or perforation but the cavity length did appear to be less than 11cm. CONCLUSIONS: While initial extrauterine placement at the time of insertion is the most common mechanism of perforation, delayed transmural migration is another mechanism that can occur.