A new Australian National University (ANU) study shows that women who smoke when pregnant are increasing the risk that their daughters will develop ovarian and breast cancer later in life.

The ANU study found that mothers who reported smoking most days while pregnant had daughters who had an earlier age of first menstruation. Lead researcher Alison Behie explains that reaching first menstruation, or menarche, at an earlier age increases the number of ovulation cycles a woman will have in her life.

This, in turn, increases the risk of developing reproductive cancers, possibly due to increased exposure to hormones, such as oestrogen. The studies utilized data on 1,5000 girls from the Australian Government study Growing Up in Australia, the Longitudinal Study of Australian Children.

Behie says, “We’re discovering more and more that major aspects of our biology, and even our behavior, are set before we are born. We know the mother’s exposure to stress, such as smoking in this case, can influence the long-term health of the child.”

According to an ANU news release, the findings are important in understanding the full range of factors that cause girls to begin menstruating early. Other studies point to the mother’s own age at menarche in addition to weight, diet, and stress during childhood. Smoking during pregnancy is typically linked to a number of health risks for children, such as reduced birth weight, but is not commonly linked with the development of reproductive cancers later in life.

Behie states, “Understanding factors that lead to early menarche, especially preventable ones, are important given these long term health implications and increased cancer risk for women.”

Source: Australian National University