These tops are great to wear over a nursing tank or under a v-neck shirt for nursing.  They do fit a little small like other reviewers have mentioned; I am 59 and 195lb (39 weeks pregnant) and normally wear med-lrg in shirts, B-cup when not nursing and C-cup when nursing.  I bought these in an XL and found they fit just right as a base layer.  They do hug a bit and if I wanted a looser fit could have gone with the 2XL, but I am happy with the slightly snugger fit for my purposes.  I would have guessed they fit like a medium in most shirts.  I wish I would have had these shirts when nursing my first, as I always felt nursing shirts and tanks were too low-cut on me.  Looking forward to using these a ton!