Gaining the right amount of weight helps your baby grow well and lowers the risk of some complications. The healthy range depends on your weight before pregnancy.
Recommended weight gain by BMI (one baby)
These ranges come from the Institute of Medicine (IOM) and are supported by ACOG:
- 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)
If you are expecting twins, the ranges are higher: 17 to 25 kg for a healthy BMI.
When the weight goes on
Most people gain only 0.5 to 2 kg in the first trimester. After that, weight gain is steadier, at around 0.35 to 0.5 kg a week for a healthy BMI.
Where the weight goes
The baby makes up only part of it. The placenta, amniotic fluid, a larger uterus and breasts, extra blood and body fluid, and fat stores for breastfeeding all add to the total.
Healthy habits
- You do not need to eat for two. Extra energy is usually only needed in the second and third trimesters.
- Choose nutritious foods most of the time and stay active.
- Do not diet to lose weight in pregnancy unless your doctor advises it.
- Talk to your doctor or midwife if you are worried about gaining too much or too little.
See your personal healthy range for this week with our Pregnancy Weight Gain Calculator.