Rarely will a cosmetic plastic surgery patient who has had a reduction mammoplasty and maintains her weight will see an increase in breast size. Although very uncommon, it can happen. The breasts will go through normal changes with aging and gravity. The main cause for the breast to increase in size is from weight gain and/or pregnancy, especially in a patient who has a very high percentage of fat rather than glandular tissue. Also, breast size can increase for the young woman who had a breast reduction surgery before fully maturing. See the previous blog on juvenile breast hypertrophy.