For years, researchers have known that breast cancer risk is reduced in women who have children and are not genetically predisposed to developing the disease. In fact, normal-risk women who deliver their first child before the age of 20 have a two fold reduction in risk compared to women who wait until after age 35. For women who have a family history of breast cancer and are carriers of the BRCA1 or BRCA2 gene mutations, the impact of having children was not clear. Some evidence even suggested that having a child may actually increase the risk of breast cancer in this group. Now, new research shows women with this genetic mutation (who have a 65-80% chance of developing breast cancer in their lives) may also benefit from childbirth.
A study published in the April 19th issue of the Journal of the National Cancer Institute examined the role of pregnancies in more than 1600 women with BRCA mutations. The results showed that additional, full term pregnancies in women with the genetic mutation cuts the risk of developing breast cancer. The reduction in risk only appears in women after the second child is born, with each child reducing the risk by 14%. The influence of timing of the first pregnancy varies in women with breast cancer gene mutations. Women with the BRCA1 mutation have a reduced risk if their first child is born after 30 years of age as compared with prior to 20 years, while BRCA2 mutation carriers have an increased risk if the first child is born after 20 years of age. These figures may clear up some of the previous confusion on breast cancer risk and pregnancies in high-risk populations of women.
Posted by Dr. Jennifer Stagg on September 1, 2006 01:31 PM
