Menopause that begins before age 40 is considered premature.
The Womenshealth.gov website explains these possible causes of early menopause:
- Medical treatments, from chemotherapy or radiation, or surgical removal of the ovaries.
- Chromosomal abnormalities affecting the ovaries.
- A family history of early menopause.
- A medical problem, such as rheumatoid arthritis or thyroid disease.