I was advised to gain 25 lbs. I gained 23 with my daughter and 21 with my son. I didn't do anything to prevent gaining weight (I was actually on bedrest with my daughter), so I guess that's the range that my body wants to be at. I do have to say that my daughter was born at 36 weeks and my son at 38, so who knows what I would be if I made it to 40+.