 Recently, multiple modalities of progesterone analogues have been investigated and successfully used to treat complex atypical hyperplasia CAH and stage 1A, grade 1 endometrial adenocarcinoma. This body of research focuses on pre-menopausal women with the primary goal of preserving fertility by delaying or avoiding surgical therapy. Across multiple case series, the average time to complete response CR: typically defined as the absence of hyperplasia, atypia or neoplasia on a follow-up biopsy specimen is 5-9 months with 60-70 overall complete response rate and approximately 50 durable complete response rate defined as complete histologic response with no relapse of disease over the period of time studied. There have been no published randomized controlled trials to evaluate which modality of progesterone therapy is the most efficacious, and there is no consistent retrospective data to suggest superiority of any given progesterone analogue or method of administration. 