The 2020 Menopausal Hormone Therapy Guidelines Original paper

What was reviewed?

This guideline review explains how menopausal hormone therapy guidelines and vaginal microbiome evidence guide modern care across symptoms, prevention, and safety. The document defines baseline evaluation, sets clear indications and contraindications, and compares routes, doses, and combinations. It favors individualized therapy by symptom burden and risk, supports transdermal estradiol to limit thrombotic and metabolic effects, and links timing of initiation to cardiovascular outcomes. It also details care for genitourinary syndrome of menopause, notes that low-dose vaginal estrogen restores flora and acidity with minimal systemic absorption, and shows that systemic estrogen does not prevent recurrent urinary tract infections. The guidance stresses shared decisions, regular review, and careful oncologic input when breast cancer history or aromatase inhibitors are present.

Who was reviewed?

The guideline targets peri- and postmenopausal women with vasomotor symptoms, sleep and mood complaints, and genitourinary syndrome of menopause, including patients who need contraception or menstrual control during the transition. It covers women at higher risk of venous thromboembolism, stroke, or cardiometabolic disease who may benefit from transdermal estradiol, and women with premature ovarian insufficiency who need longer replacement. It also addresses women with prior breast cancer who require non-estrogen first-line options and those with recurrent UTIs who need local therapy that restores the vaginal ecosystem rather than systemic estrogen.

Most important findings

The guideline confirms that systemic menopausal hormone therapy remains the most effective treatment for vasomotor symptoms and improves menopause-specific and global quality of life. It supports the “window of opportunity” in which starting therapy before age 60 or within 10 years of menopause lowers all-cause and cardiovascular mortality, while later starts raise vascular risk. It advises that stroke and venous thromboembolism risks rise with age and oral routes, and it therefore prefers transdermal estradiol or lower doses when risk accumulates, with absolute stroke risk in younger starters remaining very low. For the endometrium, the guidance requires adequate progestogen exposure in women with a uterus and allows levonorgestrel IUS with systemic estrogen to control bleeding and protect the lining during the transition.

In GSM, the guideline states that topical vaginal estrogen (cream, tablet, ring) restores lactobacillus-dominant flora, increases epithelial maturation, and lowers vaginal pH, which eases dryness, dyspareunia, urgency, and recurrent UTIs. It notes minimal systemic absorption with low-dose vaginal estrogen but urges oncologist input for women on aromatase inhibitors. Additionally, It adds that systemic estrogen does not prevent recurrent UTIs, while local estrogen does, and it supports DHEA and ospemifene when estrogen is not suitable. It also observes that moisturizers and lubricants help symptoms yet do not rebuild the internal environment, which reinforces a microbiome-directed role for local estrogen. These points provide concrete microbiome-linked signatures: lactobacillus recovery with local estrogen, sustained acidic pH, and reduced UTI risk without systemic exposure.

Key implications

Clinicians should match route and regimen to risk, favor transdermal estradiol in women with vascular or metabolic risk, and ensure consistent endometrial protection with progestogen or levonorgestrel IUS. You should start therapy near menopause for vascular safety and avoid starting late for primary prevention alone. In GSM and recurrent UTIs, you should prioritize local estrogen to restore a lactobacillus-dominant vaginal microbiome, reserve systemic estrogen for broader symptoms, and consider DHEA or ospemifene when estrogen is unsuitable. You should involve oncology for women on aromatase inhibitors, monitor bleeding patterns, and reassess dose and route regularly. These steps align symptom relief, safety, and vaginal microbiome health in daily care.