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Childbirths and Breast Cancer Risk

Study Shows Full-Term Pregnancy Provides Some Protection

Additional Births and CancerCancer Risk

Having one child was not associated with a decrease in breast cancerbreast cancer risk. But each additional birth was found to reduce breast cancer risk by 14% in women who were 40 and older when interviewed. The association was the same for carriers of both BRCA 1 and BRCA 2 mutations.

This was not the case, however, when it came to age at first birth. Having a first child after the age of 20 was associated with an increased risk of breast cancer in BRCA 2 mutation carriers. But in BRCA 1 carriers, first childbirth at age 30 and older was associated with a decrease in breast cancer risk compared with first childbirth before age 20.

The researchers concluded that this difference may be due to chance, or that it may reflect a real difference in risk among BRCA 1 and BRCA 2 mutation carriers.

The study is published in the April 19 issue of the Journal of the National Cancer Institute.

Screening and Intervention

Women who are known to be carriers of the BRCA mutation often undergo increased surveillance, and more and more are choosing either drug or surgical interventions to reduce their risk.

Preventive mastectomy to remove breast tissue before a malignancy can develop dramatically reduces breast cancer risk, but it does not eliminate risk. Likewise, surgical removal of the ovaries has been shown to cut breast cancer risk by half in women with BRCA mutations.

American Cancer Society spokesman Len Lichtenfeld, MD, FACP, tells WebMD that genetically susceptible women should consider beginning breast cancer screening at age 30. It is also generally recommended that they get screened every six months, instead of every year.

There is also some debate about how to best screen women with BRCA mutations. Lichtenfeld says magnetic resonance imaging (MRI) and ultrasound are increasingly being used instead of mammography to screen high-risk, younger women because these techniques are believed to be more effective for identifying cancers in denser breasts.

Lichtenfeld says the newly published study should reassure high-risk women that pregnancypregnancy will not increase their risk of developing breast cancer.

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