This information is from the American Society for Aesthetic Plastic Surgery.
Breast lift, or mastopexy, is a surgical procedure to raise and reshape sagging breasts, at least, for a time. No surgery can permanently delay the effects of gravity. Mastopexy can also reduce the size of the areola, the darker skin surrounding the nipple. If your breasts are small or have lost volume for example, after pregnancy, breast implants inserted in conjunction with mastopexy can increase both their firmness and their size.
The best candidates for mastopexy are healthy, emotionally stable women who are realistic about what the surgery can accomplish. The best results are usually achieved in women with small, sagging breasts. Breasts of any size can be lifted, but the results may not last as long in heavy breasts. Many women seek mastopexy because pregnancy and nursing have left them with stretched skin and less volume in their breasts. However, if you're planning to have more children, it may be a good idea to postpone your breast lift. While there are no special risks that affect future pregnancies (for example, mastopexy usually doesn't interfere with breastfeeding), pregnancy is likely to stretch your breasts again and offset the results of the procedure.