Hemoglobin is the protein in red blood cells that carries oxygen. It is encoded by 2 genes in one's DNA. Either or both of these genes can have a sickle cell trait so that the hemoglobin produced by either or both as the case may be is abnormal. If only one gene is abnormal the individual is said to have sickle trait. If both are involved the individual has sickle cell. Under low oxygen levels the sickle hemoglobin changes shape and makes the red blood cell it is in turn into a sickle shape. Conditions that make the abormal cells sickle include lowered body temperature, infections, acidic metabolic conditions, dehydration and as mentioned lowered blood oxygen levels. The abnormal blood cells have a shorter life span and tend to get caught in the smaller blood vessels of the body. The manifestation of this depends on the percentage of total body red blood cells/hemoglobin that is abnormal. Those with only the trait (one gene) have an easier time. When the percentage is high it is associated with anemia, stunted growth, sores on the legs, heart problems etc.
The affect on cosmetic surgery and the measures needed to ensure safe surgery depend on the percentage. At low percentages you do not need to do anything different from other patients. At higher percentages the patient may need pre-surgery treatment with oxygen, blood transfusion, hydration etc. If the percentage is high the patient should probably not be having elective cosmetic surgery. Your surgeon needs to work together with a hematologist in order to ensure a smooth recovery after surgery.
In your case it is impossible to say what surgery you should have without photos or preferably a face to face examination. It sounds like you need what is referred to as a mommy makeover i.e. treatment of the abdominal area as well as the breasts. That may also mean removal of excess abdominal and/or breast skin depending on what you start with and what result you want.
My response to your question/post does not represent formal medical advice or constitute a doctor patient relationship. You need to consult with i.e. personally see a board certified plastic surgeon in order to receive a formal evaluation and develop a doctor patient relationship.