More serious risks include hematoma, which is pooling of clotted blood in the breasts. Seroma, another serious risk, is the pooling of watery blood around the implant. Though very rare, symmastia is another risk to consider. Symmastia happens when the implants move and merge into one mass.The best way to avoid these complications is to find a good surgeon. For the best plastic surgery like breast implant sizes, Beverly Hills is the place to look. Make sure your surgeon has full credentials, a great history, mal-practice insurance, references and hospital privileges. Your surgeon should have a healthy respect for your wishes and be able to guide you in the right direction. He or she should also be able to answer any questions about the risks and benefits of breast augmentation.