In the course of the menstrual cycle, the breasts are enlarged by premenstrual h2o retention and short-term advancement as affected by switching hormone amounts.[fifty five] Breast tissue commences to sort in the fourth 7 days of fetal lifetime. During the fetus, breast tissue develops along two "milk lines" that begin https://grok.com/share/c2hhcmQtMw%3D%3D_21b4ddf4-c274-418a-a078-c9d2af4898ff