If you have a difficulty determining cup size you may want to measure the breasts the way the plastic surgeons measure it. Using this technique, you need a tape measure that has markings in inches. Start at the outside of the chest where the breast begins. In general, however, it is best not to operate within the first two years after the onset of menses. An exception to this may be for massive enlargement of the breast called virginal hypertrophy .
Breasts naturally sag after menopause when they lose fatty tissue and their support weakens.
Prior to that, breasts may also show significant loss of fat and fluid after pregnancy and breast feeding. More often than not, the breasts do not actually sag, but rather they have a pseudo ptosis in the postpartum period. This can be a significant flattening and collapse of the breast. True ptosis or sagging can happen before the menopause and may actually be a congenital change just like asymmetry. Implants alone may correct mild ptosis.