Intrauterine devices (IUDs) are widely utilized, long-acting reversible contraceptives with established guidelines for timely removal. Prolonged IUD retention into the postmenopausal period is an uncommon phenomenon but may have various effects on the endometrium. We present the case of a 64-year-old female who presented with postmenopausal bleeding (PMB) and was incidentally found to have a copper T380A IUD retained in utero for 29 years. The IUD was removed without complications, and her bleeding resolved following removal. However, endometrial biopsy revealed hyperplasia without atypia. Although retention of the IUD posed no major complications for this patient, it is unknown whether its presence contributed to her presentation of PMB. Potential adverse effects and complications of prolonged IUD use are also important to consider and are discussed therein. A brief review of case reports highlighting the outcomes of prolonged IUD retention is also provided.