Analysis of information sources in references of the Wikipedia article "Ptosis (breasts)" in English language version.
...there is no medical reason to wear a bra, so the decision is yours, based on your own personal comfort and aesthetics. Whether you have always worn a bra or always gone braless, age and breastfeeding will naturally cause your breasts to sag.
These women's breasts were not being suspended by the Cooper's Ligaments when they wore a bra, so removing their bra placed some stress upon those ligaments, which ligaments require in order to develop. They will not develop without a need... without some stress or pressure placed upon them. The ligaments in a casted leg are 'on vacation'... no stress... no weight... because the doctor said "I don't want you to put any pressure on that leg for six weeks!" But when the cast came off, the ligaments had to go back to work, just like the breast ligaments had to go back to work when the bra came off, after lolling around in that bra for decades.
{{cite journal}}: Cite journal requires |journal= (help){{cite journal}}: Cite journal requires |journal= (help)These women's breasts were not being suspended by the Cooper's Ligaments when they wore a bra, so removing their bra placed some stress upon those ligaments, which ligaments require in order to develop. They will not develop without a need... without some stress or pressure placed upon them. The ligaments in a casted leg are 'on vacation'... no stress... no weight... because the doctor said "I don't want you to put any pressure on that leg for six weeks!" But when the cast came off, the ligaments had to go back to work, just like the breast ligaments had to go back to work when the bra came off, after lolling around in that bra for decades.