The relationship of estrogen and progesterone to breast disease.

The rising incidence of breast cancer, coupled with awareness of the effects of hormones on breast tissue, has resulted in fears that estrogen, progesterone or both incite or adversely affect benign and malignant breast disease. An intensive review of the hormone physiology of the breast and of the numerous studies on hormones and breast disease reveals that estrogen and especially oral contraceptives not only do not cause breast cancer but may have a slight protective effect. Also, the overwhelming evidence is that the risk of benign breast disease is substantially reduced in both current and prior users of oral contraceptives.