It's not something I'm familiar with but with all the changes your boobs go through it doesn't surprise me. Women get pitting oedema on their ankles when pregnant. It usually just means there's a wee build up of fluid or that they're swollen. As long as its not hot or inflamed I would just run it by your mw at your next appt. pregnancy really confuses and scares the crap outta me. It's not for wimps and my body continues to do stuff that scares me. My current worry being of a giant baby!