Is my weight gain on track?

Enter your pre-pregnancy height and weight, current week, and current weight — see the IOM 2009 recommended cumulative range.

Units
Pregnancy type

Based on IOM/NRC 2009 guidelines (underweight 12.5–18kg / normal 11.5–16kg / overweight 7–11.5kg / obese 5–9kg). Learn more
For reference only. Gestational diabetes, preeclampsia, and fetal growth concerns require obstetric evaluation.

How is it calculated?

Recommended weight gain in pregnancy depends on pre-pregnancy BMI and singleton/twin status (IOM/NAM 2009, adopted by ACOG):

  • Underweight (BMI < 18.5): 12.5-18 kg
  • Normal (BMI 18.5-24.9): 11.5-16 kg
  • Overweight (BMI 25-29.9): 7-11.5 kg
  • Obese (BMI ≥ 30): 5-9 kg

First trimester totals 0.5-2 kg; second-third trimesters average 0.35-0.5 kg/week for normal BMI. Twins use a separate table (17-25 kg for normal BMI).

Limitations of this estimate

This is a population-level guide with wide individual variation:

  • If pre-pregnancy BMI is uncertain, the target range will be off.
  • Gestational diabetes, hypertension, or pre-eclampsia require separate management.
  • The IOM table has no data for underweight twin pregnancies — the calculator substitutes the normal-BMI value.
  • The pattern of gain matters more than the total — sudden rapid gain can signal pre-eclampsia.
  • Loss in the first trimester from morning sickness is also within normal range.

For actual management, follow the standards of your prenatal care.

Sources

Frequently asked

What if I don't know my pre-pregnancy BMI?

Compute BMI = weight(kg) / height(m)² with your pre-pregnancy weight and height. If your pre-pregnancy weight is uncertain, use the weight measured at your first prenatal visit (6-8 weeks) — this is usually very close to pre-pregnancy weight.

ACOG guidance also recommends using the first prenatal visit weight as the baseline.

What if I go outside the recommended range?

Both over- and under-gain should be reviewed by your OB-GYN — diet alone cannot rule out gestational diabetes or pre-eclampsia.

A sudden gain of 1 kg or more per week, or new swelling, can signal pre-eclampsia and warrants prompt evaluation. Intentional dieting during pregnancy is not recommended.