Major swelling after breast reduction surery. how long before it reduces?

Talk to your surgeon: "major swelling" implies a potential problem. I don't know how long ago you had surgery or what "major" means to you. You should express your concerns to your surgeon. Potential causes range from bleeding and infection to normal.

Few Weeks: The majority of swelling after breast reduction surgery dissipates within the first few weeks after the procedure is performed. However, if patients experience significant swelling, they are best off seeking follow-up with her plastic surgeon who is in the best position to determine whether the swelling is normal or a sign/symptom of complication; provide you with a diagnosis and/or reassurance.

Timing: Swelling for all surgery occurs primarily in the first 48-72 hours with improvement over time in several stages marked by 7-10 days and 3 weeks. It is not uncommon for swelling to be confused with scarring which may cause firmness. This occurs predominantly during the first 3 weeks and then culminates at 6 weeks during the proliferative phase of wound healing.

It Depends: If the breasts are asymmetrically swollen immediately after surgery, it could be a bleeding problem which needs to be evaluated asap. If the swelling is mild, and you are in the first month after surgery, it is probably early scar tissue. If you are "swollen" after the first couple of months, it is possible that not enough breast tissue was removed at surgery.