Weight Loss and Progestin for Endometrial Hyperplasia

Inclusion Criteria: * Diagnosis of histologically confirmed complex atypical endometrial hyperplasia (AEH) or grade 1 endometrial cancer. * Patients with a previous diagnosis of AEH or grade 1 endometrial cancer who are already being followed with conservative management with oral or LNG-IUD progestin therapy are eligible. * For patients with a previous diagnosis of AEH or grade 1 endometrial cancer who have been placed on progestin prior to study entry, the duration of IUD or oral progestin use prior to trial entry should be documented. * Premenopausal woman with a uterus. * ECOG performance status of 0-2. * At least 18 years of age and no more than 45 years of age. * Undergoing uterine-sparing management (e.g. due to interest in fertility preservation, interest in uterine preservation, provider recommendation, or other reason). * BMI ≥ 30 kg/m\^2. * Prior or current receipt of progestin is allowed as above. Willingness to undergo placement of LNG-IUD at the time of study entry. * Ability to understand and willingness to sign an IRB approved written informed consent document. Exclusion Criteria: * Current, active treatment for any malignant neoplasm with chemotherapy or radiation. * Pregnant and/or breastfeeding. Participants must have a negative urine or serum pregnancy test during screening window and within 7 days prior to LNG-IUD insertion. If LNG-IUD is in place, lack of pregnancy is assumed. * Active pelvic infection at the time of IUD placement or other contraindication to the use of an IUD in the opinion of the treating physician.