Recommended Weight Gain for Normal BMI in Pregnancy
For a woman with normal BMI (18.5-24.9 kg/m²) during pregnancy, the recommended total weight gain is 11.5-16 kg (25-35 lbs), making answer B correct. 1
Evidence-Based Weight Gain Guidelines
The European Society of Cardiology guidelines explicitly state that pregnant women with normal body mass index (BMI <25 kg/m²) should gain 11.2-15.9 kg during pregnancy. 1 This recommendation aligns with the Institute of Medicine guidelines, which specify 25-35 lbs (approximately 11.5-16 kg) for normal weight women. 2
Trimester-Specific Breakdown
First Trimester:
- Target gain of 1.4-2.3 kg during the first trimester 3, 4
- No additional caloric intake required unless the woman begins pregnancy with depleted body reserves 3, 4
Second and Third Trimesters:
- Recommended rate of 0.5-0.9 kg per week 3, 4
- Add 300 kcal/day to baseline energy needs during these trimesters 3, 4
- Protein intake should be 0.75 g/kg/day plus an additional 10 g/day 3, 4
Why Other Options Are Incorrect
Option A (5-10 kg): This range is too low and falls below evidence-based recommendations for normal BMI women. This amount would be more appropriate for obese women (BMI ≥30 kg/m²), who should gain 5.0-9.1 kg or approximately 7 kg total. 1, 4
Options C and D (18-25 kg and 28-32 kg): These ranges are excessive and would increase risks of gestational hypertension, pre-eclampsia, gestational diabetes, large-for-gestational-age babies, cesarean delivery, and postpartum weight retention. 5, 4
Clinical Pitfalls to Avoid
Failing to stratify by pre-pregnancy BMI: Weight gain recommendations must be adjusted based on pre-pregnancy BMI categories, as one-size-fits-all approaches lead to adverse outcomes. 2, 6
Not monitoring early pregnancy weight gain: Approximately 20% of women gain inadequately, while many others gain excessively, both associated with poor maternal and fetal outcomes. 5, 3
Applying standard BMI calculations to women with skeletal dysplasia: These women require individualized assessment as standard BMI-based recommendations do not account for body proportions. 1