How much weight should I gain in each trimester?

First trimester: 0.5-2 kg total (morning sickness may cause temporary loss). Second trimester: about 0.4 kg per week. Third trimester: 0.3-0.4 kg per week. Most weight gain occurs in the second and third trimesters — roughly 0.4 kg weekly for normal-BMI mothers.

What happens if I gain more than the recommended amount?

Excessive gain increases risk of gestational diabetes, preeclampsia, complications during delivery, and postpartum weight retention. It also raises the baby's risk of childhood obesity. Your doctor can help adjust diet and activity without restrictive dieting during pregnancy.

Does being overweight before pregnancy change the recommendations?

Yes. The IOM recommends lower gains for higher BMIs: 7-11.5 kg for overweight (BMI 25-29.9) and 5-9 kg for obese (BMI ≥30) mothers. Underweight mothers (BMI <18.5) should gain more: 12.5-18 kg. These ranges optimize outcomes for both mother and baby.

Is it safe to lose weight during pregnancy?

Pregnancy is not the time for intentional weight loss. Even for obese mothers, the focus should be on slower gain, not loss. Some women naturally lose weight in the first trimester due to nausea — this is normal and usually not concerning if nutrient intake remains adequate.

Are the calculations on Pregnancy Weight Gain Calculator | IOM Guidelines private?

Yes, completely. All calculations are performed entirely locally inside your browser using JavaScript. No inputs or personal metrics are ever transmitted to or stored on our servers.

Pregnancy Weight Gain Calculator | IOM Guidelines

Pregnancy Weight Gain Tracker by TrimesterMetriova provides free online calculators for finance, business, health, and construction. Calculate loans, investments, fitness metrics, and project materials in seconds.Pregnancy Weight Gain: IOM Guidelines by BMIThe Institute of Medicine (IOM) recommends pregnancy weight gain ranges based on pre-pregnancy BMI. Underweight women (BMI <18.5) should gain 28-40 lbs, while obese women (BMI 30+) should gain 11-20 lbs. Gain is typically 1-4 lbs in the first trimester, then 0.8-1 lb/week in the second and third trimesters.

Pre-Pregnancy BMI

BMI Range

Recommended Gain (Singleton)

Weekly Gain (2nd/3rd Tri)

Underweight

<18.5

28-40 lbs

1.0-1.3 lbs/week

Normal

18.5-24.9

25-35 lbs

0.8-1.0 lbs/week

Overweight

25.0-29.9

15-25 lbs

0.5-0.7 lbs/week

Obese

30.0+

11-20 lbs

0.4-0.6 lbs/week