BMI & Pregnancy Energy Needs (NASEM 2023 DRI)

Enter prepregnancy age, weight, and height. BMI and gestational weight-gain targets use prepregnancy BMI. Energy needs use the NASEM 2023 DRI method: nonpregnant equation for 1st trimester; pregnancy equation for 2nd/3rd trimester (uses gestational weeks).

Used for BMI + GWG guidance. (Energy equations for 2nd/3rd trimester ideally use current weight—see below.)
Enter either feet+inches or meters. The other fields auto-fill.
Mapped to NASEM PAL categories: Inactive / Low active / Active / Very active.
If entered, this weight is used for EER (recommended in 2nd/3rd trimester). BMI/GWG still use prepregnancy weight.
Recommended total pregnancy weight gain (singleton)
  • Underweight (BMI < 18.5): 28–40 lb
  • Normal (BMI 18.5–24.9): 25–35 lb
  • Overweight (BMI 25–29.9): 15–25 lb
  • Obese (BMI ≥ 30): 11–20 lb
Twins (IOM 2009 provisional targets): Normal BMI 37–54 lb; Overweight 31–50 lb; Obese 25–42 lb.
Underweight twin pregnancy: IOM did not provide a provisional target—individualize.

See Also Nutrition Resources

Equations used (NASEM 2023 DRI) + Notes
Units: age in years; height in cm; weight in kg; gestation in weeks. PAL categories: inactive / low active / active / very active.
1st trimester: uses the nonpregnant women equation (no deposition term).
  • Inactive: EER = 584.90 − (7.01×age) + (5.72×height) + (11.71×weight)
  • Low active: EER = 575.77 − (7.01×age) + (6.60×height) + (12.14×weight)
  • Active: EER = 710.25 − (7.01×age) + (6.54×height) + (12.34×weight)
  • Very active: EER = 511.83 − (7.01×age) + (9.07×height) + (12.56×weight)
2nd/3rd trimester: pregnancy equation + energy deposition/mobilization term.
  • Inactive: EER = 1,131.20 − (2.04×age) + (0.34×height) + (12.15×weight) + (9.16×gestation) + deposition
  • Low active: EER = 693.35 − (2.04×age) + (5.73×height) + (10.20×weight) + (9.16×gestation) + deposition
  • Active: EER = −223.84 − (2.04×age) + (13.23×height) + (8.15×weight) + (9.16×gestation) + deposition
  • Very active: EER = −779.72 − (2.04×age) + (18.45×height) + (8.73×weight) + (9.16×gestation) + deposition
Deposition/mobilization term by prepregnancy BMI:
  • Underweight: +300 kcal/day
  • Normal weight: +200 kcal/day
  • Overweight: +150 kcal/day
  • Obese: −50 kcal/day
This calculator uses prepregnancy BMI category for this term, consistent with how the term is described in the 2023 DRI report.
Important: The 2023 pregnancy equations are defined using a woman’s current weight in pregnancy. If you only enter prepregnancy weight, later-trimester EER may be underestimated.
References
  1. National Academies of Sciences, Engineering, and Medicine (NASEM). Dietary Reference Intakes for Energy (2023). Publication page
  2. NASEM (2023). Dietary Reference Intakes for Energy — pregnancy equations and deposition term (2nd/3rd trimester). NAP (chapter excerpt showing pregnancy EER equations)
  3. NASEM (2023). Example text describing pregnancy EER equation structure and deposition term. NAP (chapter excerpt with worked example)
  4. ACOG Committee Opinion. Weight Gain During Pregnancy (includes singleton and twin provisional targets based on IOM 2009). ACOG