Weight gain during pregnancy varies by trimester and is influenced by pre-pregnancy BMI. Here’s a general guideline for weight gain each trimester based on BMI:
- First trimester (all BMI categories): Gain about 0.5 to 2 kg (1.1 to 4.4 lbs) total.
Then, weight gain is gradual in the second and third trimesters, approximately:
| Pre-pregnancy BMI | Total Weight Gain (kg) | Weight Gain Rate 2nd & 3rd Trimester (kg/week) | Approximate Monthly Gain 2nd & 3rd Trimester (kg) |
| Underweight (<18.5) | 12.5–18 kg | 0.4 kg (1 lb) | 1.6 to 2.6 kg |
| Normal weight (18.5–24.9) | 11.5–16 kg | 0.4 kg (1 lb) | 1.5 to 2.3 kg |
| Overweight (25–29.9) | 6.8–11.3 kg | 0.27 kg (0.6 lb) | 1.0 to 1.5 kg |
| Obese (≥30) | 5–9 kg | 0.23 kg (0.5 lb) | 0.8 to 1.2 kg |
This corresponds to roughly half to 2 kg gain in the first trimester, followed by gradual consistent weekly gain varying by BMI category in the remaining trimesters.
Exact recommended weight gain depends on individual health circumstances and should be discussed with a healthcare provider for personalized guidance.
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