The most significant risk factor for breast cancer remains age, Cancer Research UK stressed this week.
Cancer information officer, Alison Ross, said that women who become mothers later in life have an increased risk of breast cancer, but this increased risk is "relatively small".
Ms Ross said: "The strongest risk factor for breast cancer is age - the older the woman, the higher her risk and four out of five cases occur in women over 50."
She added that it was very important for women in this age group to have their breasts screened regularly.
According to research by the charity, the relative risk of developing breast cancer increases by three per cent for each year childbearing is delayed.
The research also identifies that women who go through the menopause later are at an increased risk, with post-menopausal women being less likely to contract breast cancer than pre-menopausal women of the same age.
Other factors influencing risk include number of offspring, weight, alcohol consumption and breastfeeding.