Evidence does suggest that women who never have children are at a slightly elevated risk of breast cancer. To understand why this is the case, you need to understand the connection between estrogen and breast cancer. Estrogen in itself does not cause cancer—it is an essential part of a woman's physiology. However, estrogen’s principal function is to speed the process of cell proliferation. So it follows that estrogen can increase the chance of a mutation occurring and/or encourage the growth of cancerous cells once they appear. The more estrogen a woman is exposed to during her lifetime, the greater the opportunity for the hormone to promote the growth of a tumor. During pregnancy, estrogen production drops off. So it follows that women who have never been pregnant have had more exposure to estrogen during their lifetime, which puts them at a slightly higher risk for breast cancer. |
