Mine sort of scaled down in proportion to the rest of me, until the last 10 pounds or so, when I've almost certainly dropped at least one cup size. (I have dropped many, many band sizes along the way.) I am guessing the cup size thing, based on how my current bras fit (perfectly in the band, getting quite roomy in the cups) but I'll know for sure when I go back for my next fitting, which will be as soon as I've knocked off these last five pounds I want to lose, but I wouldn't be surprised to drop another cup size; it's down to my bust and a little bit of waist-and-belly fat at this point. I am totally OK with it, since I'm not in any danger of becoming flat-chested, and in fact, wouldn't be at all unhappy to land a size or two smaller.

I lose a ton of weight in my chest right near the beginning and then things shifted and I got some back. When I started eating low carb I feel like my butt hips and waist shrunk and my boobs returned!

I was probably a DD at my highest weight but continued to stuff them in a D cup. I'm older than the OP (47) and breastfed 2 kids so I am probably in the minority here. I lost alot of breast tissue in the last 15 lbs or so. I should probably wear a C cup, but again, continue to wear a D cup, because I have lots of loose skin under my arms and the D cups are cut higher for more coverage. My boobs look kind of sad and droopy but I've come to terms with them.

I was wondering the same thing, it seems with my weight gain my boobs just kept getting bigger and bigger, I want them to shrink with the rest of me, I find shirt shopping and bra etc is much easier at a B, so hopefully I will go back down to that.

It depends on whether your breasts are composed of a a significant amount of fat. If there is a good amount of fat there, you could still lose it. If it's largely breast tissue, you won't.