When you're young, single and having a drink, thoughts of pregnancy, or worse, cancer tend to not be on your mind.
Yet new Cancer Council Victoria research has shown for the first time that women who drink between puberty and their first pregnancy are more likely to develop breast cancer later in life.
The study of 13,000 Melbourne women began in the 1990s and a report released this week found those who drank before their first pregnancy had a one in seven chance of being diagnosed with breast cancer, while teetotallers had a one in nine chance.
Doctor Harindra Jayasekara told The Huffington Post Australia it was a time when a woman's body was changing.
"That time between the age of about 15 and your first pregnancy is when a woman is particularly vulnerable to the carcinogenic effects of alcohol," Jayasekara said.
Study co author Dallas English told HuffPost Australia things changed after a woman became pregnant that made them less susceptible to the carcinogenic effects of alcohol.
"Breast tissue is pretty immaterial before puberty then it develops quite rapidly. That first full pregnancy marks a change in susceptibility of breast tissue because you don't get as much cell turnover.
"That's not to say women are immune to the carcinogenic effects of alcohol after pregnancy."
The duo said alcohol tended to be more damaging, the more you drank.
"The evidence pointing to alcohol intake causing cancer is pretty strong, this is another piece of evidence."Suggest a correction