Swollen breasts may be caused by hormonal fluctuations. Female hormones play a major role in the development of the breast, estrogen and progesterone can help a woman’s breasts to develop, which will appear cosmetically as enlarged breasts. A more obvious example of this is the swelling of the breasts that may occur when a young girl enters puberty. The first sign of female puberty is breast development, which is mainly caused by the high levels of female hormones that begin to be produced during puberty. As a woman enters puberty, the ducts and lobes of the breast develop due to female hormones, giving the appearance of swollen or enlarged breasts. In addition, adult women’s hormone levels can also cause female volume changes. Adult women may experience breast enlargement when their breast ducts expand due to rapidly increasing levels of the hormone estrogen near the onset of menstruation. On the 21st day before menstruation, women also experience a significant increase in the hormone progesterone, which can trigger breast enlargement and sometimes cause swelling, pain and discomfort.