A new study has found that drinking greater levels of alcohol before pregnancy heightens the risk of developing breast cancer.
The research found that breast cancer risk increased by 11% for every 10 grammes (just over a unit) consumed.
Women who consumed roughly two units of alcohol a day faced a 34% increased risk of developing breast cancer after their first pregnancy compared to non-drinkers.
The study, published in the Journal of the National Cancer Institute, observed the drinking patterns of 91,000 women between the ages of 15 to 40.
Alcohol consumption in four age periods were obtained by asking participants about the total number of alcoholic drinks consumed at different ages: 15-17, 18-22, 23-30, and 31-40.
Of the women observed, a total 1,609 of breast cancer and 970 cases of benign breast disease were identified.
Researchers found that the link between drinking and breast cancer was at its strongest for women who started their families later in life.
Lead researcher Dr Ying Liu, says the findings “lend support to the hypothesis that alcohol intake, particularly before first pregnancy when breast tissue is likely at its most vulnerable stage, may play an important role in the etiology of breast cancer.”
She added: “These findings have potentially important implications for breast cancer prevention.”