I was just replying to the "worst comment so far" that I've received, and I realized we should do "Best comment" that you've had pregnancy-related. It could be a compliment you didn't expect.
Here are my 2 favorites:
2 different coworkers told me today that I looked "so good" and beautiful. (I needed that because my belly is definitely out there - it's seriously popped out over the last 2-3 weeks)
My mother said "I'm so happy you finally gained some weight. You looked like you'd lost so much weight when we saw you last month." (This is definitely a compliment coming from MY mother!)