Giving Birth Increases Risk for Breast Cancer (Before Eventually Offering Protection from It)

New research out of the University of North Carolina Lineberger Comprehensive Cancer Center and the Institute of Cancer Research (London) suggests that women who have children might be at a higher risk for developing breast cancer than women who have not borne any children.  More specifically, breast cancer risk was higher within five years of giving birth to women under the age of 55, increasing risk by 80 percent more than women who had not given birth.

This somewhat contradicts previous studies that suggest childbirth can offer protection from breast cancer.  Analysis of the results says that while this “protection” still exists, it can take more than 20 years after childbirth to go into effect.

For the study, researchers looked at data taken from nearly 890,000 women, of varying ages, to find that the risk seems to continue at least twenty years after childbirth.  More specifically, the study determined that the risk of developing breast cancer increases for 24 years after a women’s most recent child, but peaks in the fifth year after birth.  The risk starts to fall again—albeit, obviously, slowly—after 24 years and will reach its lowest marker again in the 35th  year.

According to Dr. David Agus, who is the director of the USC Norris Westside Cancer Center, the results of this study will very likely change the way doctors screen for and assess breast cancer. For example, Dr. Agus says, women might normally be screened, by default, at the age of 50 but breast cancer risk may increase simply within the first five years after giving birth. Thus, a woman who has a baby at 35 might need a breast cancer screening at 40, even if she is in otherwise excellent health.

Agus points out, of course, that the risk for developing breast cancer is still more common later in life—starting at age 50, for example—but this decreased risk at 30 or more years after giving birth is certainly a promising sign.  Indeed, younger women remain at the lowest risk for developing breast cancer, but this study could help to establish a long-term cancer prevention plan, especially for women who want to have a family.