Micronized Progesterone Versus Norethisterone Acetate in Combination With Estrogen as Menopausal Hormone Therapy

Postmenopausal women with climacteric symptoms will be randomized (1:1) to double blind treatment with oral mP or NETA in combination with oral estradiol. For the breast part, a power analysis revealed that 91 women/group would be sufficient to detect a significant difference in mammographic breast density between the groups at the 5%-level (two-sided) with 80% power. Considering the estimated rate of discontinuation and incomplete data, the target sample for the breast part is 260 patients. For the endometrial part, it is estimated that two or less women with serious adverse endometrial outcomes would result in an annual incidence of endometrial pathology of 0.67% or less with an upper bound of the one-sided 95% CI of 2.08% or less. Considering the estimated rate of discontinuation and incomplete data in the mP + estradiol group, the target sample for this part of the study is 390 patients. The total number of patients in part 1 and 2 will be 520.

Mammography at baseline and after 12 months of treatment will be assessed by independent radiologists at the Karolinska University Hospital blinded to treatment. In addition to visual judgment, a computer based quantitative assessment will be performed. All mammograms will be anonymous so that the operator will be unaware of the patient's identity and type of treatment. Percentage change in mammographic density will be evaluated and compared between the groups.

Endometrial biopsies at baseline and after 12 months of treatment will be evaluated by two independent pathologists at the Karolinska University Hospital for the incidence of endometrial pathology (hyperplasia or cancer) in the mP + estradiol group. Furthermore, immunostaining of the proliferation marker Ki-67, and other markers related to proliferation and apoptosis will be analyzed and compared between groups.

Different validated self-assessment questionnaires will be used for screening of mood disorders like depression and anxiety, as well as quality of life and menopausal symptoms. The Patient Health Questionnaire (PHQ-9) is a tool for screening, diagnosing, and measuring the severity of depression. The Hospital Anxiety and Depression Scale (HADS) is an instrument for detecting states of depression and anxiety in the setting of a hospital or medical outpatient clinic. Health related quality of life is measured using the Psychological General Well-Being Index (PGWB). The Women's Health Questionnaire (WHQ) measures menopausal symptoms. The change in scores will be compared between the groups.

Blood lipid profile, serum hormones, growth and metabolic factors, and coagulation factors will be analyzed.

The gut- and vaginal microbiome will be characterized and compared between groups.

Inclusion criteria

• Healthy and naturally postmenopausal women (more than one year since last menstruation or FSH > 40 IE/L) with climacteric symptoms (sweating, hot flush and/or sleep problems) that adversely affect the quality of life
• Age 45-60 years
• BMI > 19 kg/m2 and ≤ 32 kg/m2
• Intact uterus
• In case of previous MHT use, washout 8 weeks for oral MHT and 4 weeks for transdermal MHT or local estrogen treatment before screening
• Written informed consent

Exclusion criteria

• Previous history or risk factors for breast cancer, breast cancer in situ or abnormal mammogram at baseline as assessed clinically by a radiology expert
• Previous history or risk factors for endometrial cancer or hyperplasia or abnormal/proliferative endometrial biopsy at baseline
• Vaginal bleeding
• Any concomitant medical treatment except for well-controlled hypertension, non-insulin treated type 2 diabetes, asthma and hypothyroidism
• History or presence of or risk factor for cardiovascular disease including thromboembolic disorder or cerebrovascular disease
• History or presence of liver and gallbladder disease, familial hyperlipidemia, epilepsy or classical migraine with aura
• History or presence of clinically significant depression or other psychiatric disorder that might in anyway compromise the performance of the trial or undermine its scientific validity
• Porphyria, Systemic lupus erythematosus and otosclerosis
• Current use of MHT or local estrogen treatment
• Alcohol and/or drug abuse
• Clinically significant findings on physical and/or gynecological examination at baseline
• Hypersensitivity to any of the study treatments