2-4 lbs, A healthy weight gain for a patient at her ideal weight is 1/2 to 1 lb. Per week, or 2-4 lbs. Per month.
No set amount. Normal weight gain for a woman of normal weight is 25-35 pounds during pregnancy. This averages out to 1-2 pounds per week. Early in the pregnancy some woman will lose a little weight due to morning sickness. As the pregnancy progresses, the weight gain per week will increase. As long as you're eating a healthy diet you shouldn't have to worry too much.
It depends. In the 1st trimester it is common to gain no weight or even lose, typically in the first 3 months weight gain is limited to 10 lbs or less. In the second trimester normal weight gain pattern is about 1/2 lb per week, but it may plateau and then jump, depending on when the fetus has a growth spurt. In the last 8-12 weeks of pregnancy expect about3/4 lb per week. Advise your doc re: big changes.