Swelling

When does swelling become a concern? My sister is 2 weeks ahead of me, making her 30 weeks. Her feet get so swollen they tingle, go numb and hurt. The swelling goes up in her legs. I know swelling is normal, and happens all the time. She said that she tells her OB, and he doesn't seem concerned, and just tells her she is fine without checking for anything. I have he same dr, and I can't see him just ignoring it. But maybe I'm wrong. When should she seek another opinion. I told her if she feels like something is wrong, go to urgent care or the emergency room. But what are your thoughts? I will get a picture of how bad they are and post in the comments of it let's me