Higher Placental Weight Associated with Increased Maternal Breast Cancer Risk
Maternal Breast Cancer
Women with a higher placental weight in prior pregnancies have an increased risk of breast cancer, possibly from the hormones produced by the placenta, according to a study in the November 16 issue of JAMA.
Hormonal factors play a key role in the development of breast cancer, according to background information in the article. Early menarche (first menstruation), late menopause, and long-term use of hormone therapy have been shown to be associated with increased risk of breast cancer. Serum levels of estrogens, progesterone and placental growth hormones are many times higher during pregnancy than during other periods of life, and pregnant women also are exposed to elevated levels of insulin-like growth factors. During pregnancy, these markers have been inconsistently associated with subsequent risk of breast cancer in the mother. It has been hypothesized that placental weight could be an indirect measure of hormone exposure during pregnancy.
Sven Cnattingius, M.D., Ph.D., of Karolinska Institutet, Stockholm, Sweden, and colleagues investigated the possible associations between indirect markers of hormonal exposures during pregnancy, such as placental weight, offspring