Menopause: Symptoms and causes (Mayo Clinic)

Tier 1: Established: peer-reviewed research or government health authority
Publisher: Mayo Clinic · Published: August 6, 2026 · Accessed: August 24, 2026

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Claims this source supports

• Perimenopause typically lasts 2 to 8 years, averaging about four years, during which the amount of hormones the ovaries make varies.
• Hormone changes during the transition can cause irregular periods, vaginal dryness, hot flashes, night sweats, sleep problems, mood changes, and trouble finding words and remembering (brain fog).
• Menopause is diagnosed after 12 months without a menstrual period; average age of natural menopause in the United States is 51.
• See a healthcare professional promptly for any vaginal bleeding after menopause.
• Surgery that removes the ovaries, called oophorectomy, causes instant menopause: periods stop, and hot flashes and other menopausal symptoms are likely and can be severe because hormones drop all at once rather than slowly over several years.
• Surgery that removes the uterus but not the ovaries (hysterectomy) most often does not cause instant menopause; the ovaries keep making estrogen and progesterone for a time, though periods stop.
• Chemotherapy and radiation therapy can cause menopause; periods sometimes return after chemotherapy.
• For women who reach menopause unusually early, healthcare professionals most often suggest hormone therapy, taken at least until the typical age of menopause, to help protect the brain, heart, and bones.