Asian Girl With Full Breasts

As breasts are mostly composed of adipose tissue, their size can change over time. This occurs for a number of reasons, most obviously when a girl grows during puberty and when a woman becomes pregnant. The breast size may also change if she gains (or loses) weight for any other reason. Any rapid increase in size of the breasts can result in the appearance of stretchmarks.
It is typical for a number of other changes to occur during pregnancy: in addition to becoming larger, the breasts generally become firmer, mainly due to hypertrophy of the mammary gland in response to the hormone prolactin. The size of the nipples may increase noticeably and their pigmentation may become darker. These changes may continue during breastfeeding. The breasts generally revert to approximately their previous size after pregnancy, although there may be some increased sagging and stretchmarks.
The size of a woman's breasts may fluctuate during the menstrual cycle, particularly with premenstrual water retention. An increase in breast size is a common side effect of use of the combined oral contraceptive pill.
Breasts sag if the ligaments become elongated, a natural process that can occur over time and is also influenced by the breast bouncing while exercising (sports bra). Breasts can decrease in size at menopause if estrogen levels decline.