Recommended total weight gain
Based on the 2009 Institute of Medicine (IOM) guidelines, which ACOG supports. Your doctor may give you a different target.
How much weight should I gain in pregnancy?
The healthy amount depends on your body mass index (BMI) before pregnancy. These are the Institute of Medicine (IOM) ranges for one baby:
- Underweight (BMI under 18.5): 12.5 to 18 kg (28 to 40 lb)
- Healthy weight (BMI 18.5 to 24.9): 11.5 to 16 kg (25 to 35 lb)
- Overweight (BMI 25 to 29.9): 7 to 11.5 kg (15 to 25 lb)
- Obese (BMI 30 or more): 5 to 9 kg (11 to 20 lb)
For twins, the ranges are 17 to 25 kg for a healthy BMI, 14 to 23 kg if overweight, and 11 to 19 kg if obese.
How weight gain is spread across pregnancy
Most people gain only 0.5 to 2 kg (1 to 4.4 lb) in the first trimester. After that, gain is steadier: about 0.35 to 0.5 kg (0.8 to 1 lb) a week for a healthy BMI, more if underweight and less if overweight or obese. The calculator uses these weekly rates to estimate a healthy range for your current week.
Where the weight goes
Only part of the gain is the baby. The rest is the placenta, amniotic fluid, a larger uterus and breasts, extra blood and fluid, and fat stores that help with breastfeeding.
Tips for healthy weight gain
- You do not need to eat for two. Extra calories are usually only needed in the second and third trimesters, and only a few hundred a day.
- Choose vegetables, fruit, whole grains, lean protein and dairy.
- Stay active with moderate exercise most days, unless your doctor advises otherwise.
- Do not try to lose weight during pregnancy unless your doctor recommends it.
Frequently asked questions
Is it bad to gain too much weight in pregnancy?
Gaining much more than recommended is linked to a higher chance of gestational diabetes, high blood pressure, a large baby and keeping weight after birth. Your doctor can help if you are worried.
What if I am not gaining weight in the first trimester?
Many people gain little or even lose a little early on, often because of nausea. Mention it at your appointment, but it is usually not a concern.
Does this calculator work for twins?
Yes. Choose Twins. The IOM gives total ranges for twins, and the weekly figure is a rough guide only.
Is my information saved?
No. The calculation runs in your browser and nothing is stored.