Question: how much weight should i gain in first trimester if underweight?
Answer: You should gain: 25-35 pounds if you were a healthy weight before pregnancy, with a BMI of 18.5-24.9. 28-40 pounds if you were underweight before pregnancy with a BMI of less than 18.5. 15-25 pounds if you were overweight before pregnancy with a BMI of 25-29.9.