How much weight you should put on during pregnancy depends on your weight pre-pregnancy. There should also be considerations if you are carrying twins or triplets.
a healthy BMI range is 18.5-24.9. If you are within this range, you should expect to put on between 25 and 35 pounds (lbs).
If you have a BMI, below 18.5 you should gain 28 and 40 pounds (lbs). If you have a high BMI, above 25, you should gain between 15 and 25 pounds (lbs).
If your BMI exceeds 30, total weight gain should be between 11 and 20 pounds.