Recurrent extreme breast involution following pregnancy and susceptibility to breast cancer: a hypothesis.
Nine multiparous women were found to have breast development resembling the prepubertal "flat-chested" state. During their pregnancies, the breasts of all nine women had developed and enlarged, and five had successfully nursed for two or more months. The remaining four women did not attempt to breastfeed. Following cessation of lactation in the women who had breastfed, and after delivery in those who had not suckled, the breasts of all nine women completely regressed to their prepregnant "flat-chested" physical state. Based on the findings of normal health and regular menses in these women, we hypothesize that the breast epithelium of these and other flat-chested women may have an elevated threshold of estrogen sensitivity in the nonpregnant state which may reduce susceptibility to mechanisms of carcinogenesis.
D000328:Adult; D001284:Atrophy; D001940:Breast / Q000503:physiopathology; D001943:Breast Neoplasms / Q000503:physiopathology*; D002681:China / Q000208:ethnology; D004967:Estrogens / Q000502:physiology; D005260:Female; D006801:Humans; D007774:Lactation; D008875:Middle Aged; D011247:Pregnancy; D014481:United States
D004967:Estrogens