How much weight should I gain during pregnancy?
The Institute of Medicine (now the National Academy of Medicine) recommends a total gain based on your BMI before pregnancy. Most of it comes in the second and third trimesters.
| Pre-pregnancy BMI | Total gain, one baby | Weekly, 2nd and 3rd trimester | Total gain, twins |
|---|---|---|---|
| Underweight (under 18.5) | 28–40 lb | 1–1.3 lb | No guideline |
| Healthy (18.5–24.9) | 25–35 lb | 0.8–1 lb | 37–54 lb |
| Overweight (25–29.9) | 15–25 lb | 0.5–0.7 lb | 31–50 lb |
| Obese (30 and over) | 11–20 lb | 0.4–0.6 lb | 25–42 lb |
Example: at 5 ft 5 in and 140 lb before pregnancy, BMI is 23.3, in the healthy range. The goal is 25–35 lb in total. By week 20, a healthy gain is about 1.1 + 0.8 × 7 = 6.7 lb to 4.4 + 1 × 7 = 11.4 lb.
Where the weight goes
At full term, a typical gain is roughly 7 to 8 lb for the baby, 1 to 2 lb for the placenta, 2 lb of amniotic fluid, 2 lb of uterus, 2 lb of breast tissue, 4 lb of extra blood, 4 lb of other fluid and 5 to 9 lb of fat stores for breastfeeding.
Gaining a little more or less than the range isn't cause for alarm on its own; your provider looks at the overall pattern. Track your progress with the pregnancy week calculator and find your due date with the due date calculator.
Frequently asked questions
How much weight should I gain in the first trimester?
About 1.1 to 4.4 lb (0.5 to 2 kg) in total for most people. Some lose a little because of morning sickness.
How much weight should I gain with twins?
For a healthy pre-pregnancy BMI, 37 to 54 lb. The range is 31 to 50 lb if overweight and 25 to 42 lb if obese.
Is it safe to lose weight during pregnancy?
Generally, pregnancy isn't the time to diet. If your BMI is high, your provider may suggest gaining less, but talk to them before cutting calories.
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