Does HRT cause breast cancer?
Reviewed by Kindr Health Clinical Team · Last reviewed July 3, 2026
Answer published
The data are more reassuring than headlines suggest. Estrogen-only therapy (for women without a uterus) showed no increase — and possibly a decrease — in breast cancer risk in the 7-year Women’s Health Initiative follow-up. Combined estrogen plus medroxyprogesterone (a synthetic progestin) showed a small absolute risk increase of about 1 extra case per 1,000 women per year after 5 years of use. Micronized progesterone (Prometrium) has not shown the same signal in European cohorts. For context, drinking 1 alcoholic drink/day and being overweight each carry larger breast cancer risk than HRT.
People also ask
- Can I drink alcohol on HRT? →
Moderate alcohol is not contraindicated with HRT, but alcohol independently worsens hot flashes, sleep, and breast cancer risk in midlife.
- Is hormone replacement therapy (HRT) safe? →
For healthy women under 60 or within 10 years of menopause, modern HRT is considered safe and effective by NAMS, the Endocrine Society, and ACOG.