Effects of Estradiol on Menopausal Breast

Inclusion Criteria: * Naturally postmenopausal, symptomatic, apparently healthy women, with the need for hormone therapy aged 50 - 70 years with a BMI \>18 and ≤30 kg/m2 and without any previous history of breast disease will be recruited for the study. * They should be amenorrheic for at least 12 months or less than 12 months with S- FSH values \>40 IU/L. * They should be free of any sex hormone treatment for at least three months before inclusion. Exclusion Criteria: * General contraindications for HT according to Swedish product label. Age \>60 years. BMI ≤18 or ≥30 kg/m2. * Any previous history of cancer. * Any previous history of breast disease or abnormal mammogram. * In addition: hypertension (systolic BP \>160 mm Hg or diastolic \>100 mm Hg), hyperlipidemia (total cholesterol \>8.0 mmol/L or triglycerides \>3.0 mmol/L), diabetes mellitus, history of thromboembolic disease, heart failure, liver disease or porphyria, undiagnosed vaginal bleeding. No sex hormone treatment for at least three months before inclusion. * No concomitant treatment known to influence hormone metabolism (warfarin, rifampicin, carbamazepine, griseofulvin, hydantoins, primidone, barbiturates, broad spectrum antibiotics) is to be accepted.