Im 5'4 38D 170lbs, I usually wear a size M-L but decided to size up to an XL based on other reviewers' recommendations stating this runs small. I do like my cardigans to be a little looser but this just didn't look right.  Unfortunately it's material and thickness gave it more of a "weighed down" look than the relaxed fit that I typically go for. I recommend going with your usual size.