Higher risk of breast cancer for women after childbirth, research finds
The increased risk for breast cancer after childbirth may last more than 20 years, researchers reveal.
The risk may be enhanced when a woman is older at first birth or has a family history of breast cancer, and is not lessened by breastfeeding.
Researchers pooled data from 15 prospective cohort studies to characterise breast cancer risk in relation to recent childbirth.
The data showed that, compared with women of the same age who had never given birth, women who had given birth had an increased risk for breast cancer that peaked about five years after birth and continued for about 24 years after birth.
The increased risk was seen for both oestrogen receptor (ER) positive and ER negative breast cancer. Breastfeeding did not modify risk patterns.
According to the researchers, these findings show that risk factors for breast cancer can differ between older and younger women, and should be considered in combination with other characteristics than may influence risk, such as a family history of the disease.
The research was co-authored by University of North Carolina Gillings School of Global Public Health, the Institute of Cancer Research in London and the National Institute of Environmental Health Sciences in North Carolina.
Access the full study here.