They just changed our rules re: exit row seating. If you use a seatbelt extension, you are not allowed in the exit row. I think it's a great rule, but I hate being the bearer of bad news. My Mom is overweight and I know she would be offended, so I can fell thier pain. As for a very large pregnant woman, I would not let her sit there. I guard those seats pretty well, and would not feel comfortable with her sitting there. Anything/anyone who would impede an evacuation, cannot sit there. Also, if you are a member of a family and your family is in another row, you cannot sit there. If there is an emergency, you would be looking for your family and not helping with the evacuation.