The total expected weight gain during pregnancy depends on the mother's pre-pregnancy BMI (Body Mass Index). Here are the general guidelines from the Institute of Medicine (IOM):
Recommended Total Weight Gain by BMI Category:
Pre-pregnancy BMI Category Recommended Gain
18.5 Underweight 28–40 lbs (13–18 kg)
18.5 – 24.9 Normal weight 25–35 lbs (11–16 kg)
25 – 29.9 Overweight 15–25 lbs (7–11 kg)
30 Obese 11–20 lbs (5–9 kg)
Weight Gain Breakdown by Trimester:
1st Trimester (0–13 weeks): 1–4.5 lbs (0.5–2 kg)
2nd & 3rd Trimesters:
About 1 lb (0.4–0.5 kg) per week if normal BMI
What Makes Up the Weight Gain?
Baby: 7–8 lbs
Placenta: 1.5 lbs
Amniotic fluid: 2 lbs
Breast tissue, blood, uterus, and fat stores: remainder
