Pregnancy Weight Gain Calculator
IOM-recommended gain by pre-pregnancy BMI. Normal: 11.5-16kg. Underweight: 12.5-18kg. Overweight: 7-11.5kg. Obese: 5-9kg...
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How It Works
IOM-recommended gain by pre-pregnancy BMI. Normal: 11.5-16kg. Underweight: 12.5-18kg. Overweight: 7-11.5kg. Obese: 5-9kg.
Quick Reference
Normal BMI
IOM guideline
11.5-16 kg total
Underweight BMI
IOM guideline
12.5-18 kg total
Overweight BMI
IOM guideline
7-11.5 kg total
Tips & Shortcuts
First trimester: only 1-2kg total.
Second and third: ~0.5kg/week for normal BMI.
Common Mistakes
Same gain expected each trimester
Most gain occurs in second and third trimesters.
Treating range as strict target
Ranges are guidelines. Individual variation is normal.
Frequently Asked Questions
IOM guidelines by BMI: Underweight (<18.5) → 28–40 lbs; Normal weight → 25–35 lbs; Overweight (25–29.9) → 15–25 lbs; Obese (≥30) → 11–20 lbs.
Minimal gain in the first trimester (1–4 lbs total). Most accumulates in the second and third trimesters at roughly 0.5–1 lb per week for normal-weight women.
Excess gain increases risk of gestational diabetes, preeclampsia, cesarean delivery, and difficulty losing weight postpartum.
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