I tell women they should concentrate on what they're eating on a day-to-day, meal-to-meal basis. They should have regular meals and snacks and a variety of nutrient-rich foods. That tends to work for women at risk of gaining too much and women who need to gain more.
I try to keep a pregnant woman's eyes away from the scale, because it's scary either way - whether you're gaining too much or not enough.
I'm very concerned about public awareness of obesity, especially when pregnant women are told they're gaining too much weight by a doctor. Given that scare tactic combined with the wrong information, a pregnant woman might think she needs to start dieting.