Reference summary — not medical advice or a personal risk estimate.
Late menopause (after age 55)
Quick answer
Not IARC-classified — this is not a chemical or physical agent IARC rates. Recognized as a cancer risk factor based on observational evidence. Biological / developmental. Applies to people who reach natural menopause after age 55.
Summary
Reaching menopause after age 55 is associated with a modestly higher lifetime breast cancer risk, linked to longer cumulative exposure to ovarian hormones.
What's not established
This reflects a population-level statistical association, not an individual risk figure. It does not establish a specific magnitude of increased risk for any one person, and age at menopause is largely outside a person's control.
Evidence sources
Every claim on this page traces back to one of these. Click through to read the primary document yourself.
Primary sources
NCI
NCI — Reproductive History and Cancer Risk
Last reviewed: October 2026
Official reference list
A government list some readers use alongside the primary evidence. Meyron is not affiliated with it. A chemical being listed does not by itself describe a risk from any particular product.
- California Prop 65 list
State of California's list of chemicals known to cause cancer or reproductive harm.