Girls whose mums smoked heavily when pregnant tend to start menstruating earlier than those whose mums were smoke-free, according to a new study in Denmark.
Researchers looked at the responses of 13,815 mums who were questioned about their lifestyle during pregnancy in the mid 1980s. They then asked their daughters their age when they began menstruating. More than 3,000 of the daughters were able to remember the month and year of their first period.
On average, the girls of mums who smoked in the study had their first period just after they turned 13, between three and four months earlier than the average for mums who had not smoked during pregnancy.
“For any one kid, a few months isn’t going to make much of a difference, probably,” said Dr Gayle Windham, who reviewed the findings for Reuters Health. “However, if large groups of girls begin menstruating earlier, even by just a few months, that could have an overall effect on the population,” she added.
Though most mums-to-be avoid cigarettes in pregnancy now the medical affects are well known, it is estimated about 1 in 10 women in the UK continues to smoke when pregnant. Find out more about how smoking puts your baby at risk.