Women whose firstborn children weighed more than 8.25 pounds at birth have more than double the risk of getting breast cancer, compared to women who have smaller babies according to a new study. The findings, published in the journal PLoS One, suggest that giving birth to a big baby creates a hormonal environment in the mother that’s conducive to the development of breast cancer in women later in their lives. Researchers evaluated women’s health histories, their babies birth weight, and their levels of three pregnancy hormones: estrogen, anti-estrogen and insulinlike growth factors. They found that women whose firstborn babies had a high birthweight had higher levels of estrogen and insulinlike growth factors during pregnancy, as well as lower anti-estrogen levels. However, these results demonstrate an association, not “a cause-and-effect link,” said the study researcher Dr. Radek Bukowski.
