In 2015, the ACOG released its Committee Opinion on "Endometrial Intraepithelial Hyperplasia", or EIN (CO 631). EIN is of clinical significance because it is often a precursor lesion to adenocarcinoma of the endometrium. Making the distinction between hyperplasia and true precancerous lesions or true neoplasia is super important because their differing cancer risks must be matched with an appropriate intervention to avoid under/overtreatment. As is our podcast tagline, "medicine moves fast"; coming out in September 2023, the ACOG will release a new Clinical Consensus guideline on "EIN-AEH". What are the new changes? Why are we moving from a EIN designation to EIN-AEH? Is a progestin IUS a reasonable therapeutic option for those wishing to preserve fertility after this diagnosis? In his episode, we will answer all these questions and more, focusing on this new Clinical Consensus guideline.