In the course of the menstrual cycle, the breasts are enlarged by premenstrual drinking water retention and short term development as influenced by switching hormone concentrations.[fifty five] Breast tissue commences to kind within the fourth 7 days of fetal everyday living. During the fetus, breast tissue develops alongside two "milk https://grok.com/share/c2hhcmQtMw%3D%3D_21b4ddf4-c274-418a-a078-c9d2af4898ff