After a Single Mastectomy, Why the Two Sides Settle Differently

Two great questions came in from the single mastectomy community:

1. If you had a single mastectomy with reconstruction and an implant placed on the non-cancer side for symmetry, does it look even right away? Or is there a settling period where one side is more swollen?
2. If you add fat grafting to your reconstruction, is the recovery a lot longer?

I have answers for both.

Before the timing questions, there's a more basic one I get constantly: if you're having a breast cancer reconstruction, can you have something done to the non-cancerous breast that isn't having a mastectomy?

Absolutely yes.

If you're having a mastectomy and you want a reconstruction that's larger than the size you start at, that's safe. I can say that with more confidence than usual, because my partner and I published the data: in Aesthetic Surgery Journal Open Forum (2026), we looked at direct-to-implant reconstructions after nipple-sparing mastectomy and compared patients whose implants were larger than the mastectomy specimen to those whose implants were smaller. The upsized group did not have more problems. They had a lower complication rate, and BMI, not the size difference, was the strongest predictor of mastectomy skin flap necrosis.

So if you want to come out larger, you can have an implant placed on the non-cancerous side so that you have volume symmetry. And here's the part patients rarely know: this is typically covered by insurance as a symmetry procedure.

What we do to the non-mastectomy breast depends on you. The first thing I do as a plastic surgeon is figure out how you feel about your breast right now, both its size and its position.

• You like how everything looks, and you like the size. Then we do nothing to the other side. The goal is simply to make the reconstructed breast look as similar as possible to the one we didn't operate on.
• You like your size overall, but you feel a bit droopy. Then we might do a lift on the non-mastectomy breast, with no implant on that side.
• You're droopy and you want more volume. Then we might do a lift and a small implant on the non-cancer side.
• You'd actually like to be smaller. Then we can do a reduction on that side and use a smaller implant on the mastectomy side.

There are so many different options, and what I recommend really comes down to your goals. (The reconstructed side has the same range: smaller, the same, larger, or more lifted.)

For most patients, the two sides do not look immediately symmetric. And the reason is that they're at completely different points in the healing process.

Whether you had a single-stage or a two-stage reconstruction, that implant has typically already had time to settle on the mastectomy side.

In a two-stage reconstruction, we're swapping a tissue expander for an implant. The volume stays the same. What changes is the footprint and the shape of the breast. So there's genuinely less that needs to settle on that side.

The other side is a different story: that breast has never been operated on.

So it goes through more of a settling period, exactly like any first-time augmentation patient would. And it can be even more pronounced if the implant goes under the muscle. That's less common in reconstruction these days, but with an under-the-muscle implant you go through the full settling and "fluffing" stage, where everything gradually relaxes. (That whole process, and why things feel firm before they soften, is its own timeline. Over versus under the muscle is also one of the three big reconstruction questions.)

One breast that's already settled, one breast that hasn't started. Of course they don't match at two weeks.

Here's something patients don't know about how surgery works:

Then after surgery, swelling and muscle spasms change things. What you're looking at in week one or week three is not the result. It's the result plus swelling plus a muscle that's still angry.

So don't get too excited looking at it early. Give your body time to heal. Usually by six months, everything will even out.

If asymmetry persists past that window, that's a real conversation to have, and asymmetry has many separate components worth naming precisely. But some asymmetry is normal in every body, and early asymmetry is usually just timing.

Adding fat grafting to your surgery doesn't necessarily make the healing in the breast area much worse.

What it does is add a new part of your body that's sore: the donor site, where we took the fat.

And that varies enormously between people:

• Some patients tolerate liposuction great and fly right through it
• Others have a lot of pain and tenderness afterward

So yes, it can prolong your recovery — but through the donor site, not the reconstruction itself. (How fat grafting works explains why we're taking fat from somewhere in the first place.)

Here's the thing nobody warns you about:

You have to wear a compression garment, a Spanx-type garment, over the area we took the fat from, for about a month.

That is a pain, and it's a particular misery in the summer.

This leads to genuinely practical advice you won't get from a brochure: depending on the time of year and what activities you have planned, consider scheduling your fat grafting for a cooler time of year when you're less active.

A month in compression in January is a very different experience from a month in compression in July. If the timing is flexible, use that.

One more thing to go in knowing, because it's about years rather than months.

Your two breasts are going to age differently, because there are different things going on side to side: a different size implant, a different amount of tissue, a different surgical history. One side is a reconstruction. The other is your own breast with an implant behind it.

It's completely reasonable to do this, and you can get great volume symmetry. But over time you may end up with revisions to keep things sitting in the same place, precisely because the two sides don't age in step. That isn't a complication, and it isn't a sign anything went wrong. It's maintenance on two structures that were never identical.

This holds whatever was done to the other side, whether that was an implant, a lift, a reduction, or nothing at all: a reconstructed breast and a non-reconstructed breast don't age the same. Sometimes one ends up staying where it's supposed to and the other starts to come down.

So if you're choosing a one-sided mastectomy, it's important to know that multiple surgeries may be in your future just for aesthetic reasons. It's one of the things worth weighing when you're deciding between a single and a double mastectomy.

If you had a single mastectomy with reconstruction plus a symmetry implant on the other side:

• Yes, you can operate on the healthy side for volume symmetry, and it's typically covered by insurance as a symmetry procedure
• An implant isn't the only option for that side. Depending on your goals it can be nothing, a lift, a lift with a small implant, or a reduction
• Coming out larger than you started is safe, which is what our published data showed
• They usually won't look even right away, and that's expected
• The mastectomy side has already settled; the symmetry side hasn't started
• Swelling and muscle spasms change what you see after surgery, even though it looked right in the OR
• By about six months, things typically even out
• Long term, the two sides age differently, so expect possible revisions to keep them matched

And if fat grafting is part of your plan, the reconstruction recovery isn't meaningfully harder, but you're adding a sore donor site and about a month in a compression garment. Plan it for a cooler, less active stretch of the year if you can.

Healing takes time. Give your body the chance to settle before you judge the result.