There is some evidence to suggest that there may be a link between exposure to magnetic fields and the risk of breast cancer. Some researchers have proposed that if there is such a link, it may be through the effects of the hormone melatonin. This hormone, produced by the pineal gland in the brain, regulates the production of other hormones in the body, including estrogen.
Levels are low during the day and higher at night.
Reduced levels of melatonin, in turn, can increase the production of estrogen. It is known that increased estrogen levels may affect the development of breast cancer.