Mine didn't seem to do anything at all! They've never been sore, and they didn't feel like they'd gotten bigger.. but I did get stretch marks early on underneath (go figure!). I got myself some maternity bras around week 18 i think, and I was having a bit of leaking at that stage too.

They've definitely changed throughout the pregnancy tho, looking back, but I never really felt the changes iykwim. Like Jen - the areolas have definitley grown, and I'm not so worried about having only little mosquito bites I thought I was going to have to try and feed with! LOL. DH teases me now and says I have tribal woman boobs.. especially when I'm sitting leaning over my belly, they kinda sit there on top of the belly... and yes.. I look like some tribal woman! LOL.