Hormonal factors

Your exposure to the hormones oestrogen and progesterone can affect your breast cancer risk. Factors that can increase risk include:

  • Taking hormone replacement therapy (HRT) – this can increase your risk, particularly if you’re taking combined HRT (oestrogen and progesterone). When you stop taking HRT, your risk reduces again.
  • Not having children or having them after the age of 30.
  • Not having breastfed or breastfeeding for less than a year in total.
  • Starting your periods early (under the age of 12) or having a late menopause (after the age of 50).
  • Taking the contraceptive pill, although the risk reduces if you stop taking it.

Back to Potential causes of breast cancer

Age, lifestyle and risk

Your risk of developing breast cancer may increase with age, alcohol intake, being overweight and smoking.