Estrogen Administration for the Treatment of NASH in Postmenopausal Women

Inclusion criteria: * Postmenopausal women 45-70 years old * NASH by biopsy or NAFLD by imaging within 6 months of screen * Hepatitis C antibody and hepatitis B surface antigen negative * Negative mammogram within 1 year Exclusion criteria: * Heavy alcohol use * Use of NASH pharmacotherapies within 12 months of study entry * Known cirrhosis, stage 4 fibrosis on biopsy, or clinical evidence of cirrhosis or portal hypertension on imaging or exam * Participation in NASH clinical trial within 6 months of study entry * Chronic use of corticosteroids, methotrexate, amiodarone, or tamoxifen within 6 months of entry * Known diagnosis of chronic liver disease other than NAFLD or found on biopsy * Contraindication to liver biopsy including INR \> 1.5, platelets \< 50,000/mL, ascites, chronic anticoagulation (other than aspirin), biliary obstruction, peritonitis, inability to lie supine for 30 minutes * Hgb \< 10.0 g/dL or glomerular filtration rate \< 60 mL/min * Contraindications to estrogen therapy * Any vaginal bleeding, including spotting, within the last year * Active malignancy * Severe chronic illness * Use of estrogen or progesterone within a year of baseline visit * Routine MRI exclusion criteria such as the presence of a pacemaker or cerebral aneurysm clip