What is the recommended monthly weight gain for pregnant women?

Recommended Monthly Weight Gain During Pregnancy

Normal-weight women should gain 1.4–2.3 kg per month during the first trimester, then shift to 0.5–0.9 kg per week (approximately 2–4 kg per month) during the second and third trimesters. 1

Weight Gain Targets Based on Pre-Pregnancy BMI

The recommended monthly weight gain varies significantly based on pre-pregnancy body mass index:

First Trimester

• Normal-weight women (BMI 18.5-24.9): 1.4–2.3 kg per month 1
• Underweight women (BMI <19.8): 1.4–2.3 kg per month, with total pregnancy goal up to 18 kg 1
• Overweight women: Less than 50% of normal-weight rates, approximately 0.7–1.2 kg per month 1
• Obese women (BMI >30): Minimal gain, with total pregnancy target of only 7 kg 1

Second and Third Trimesters (Weekly Rates)

After the first trimester, weight gain recommendations shift to weekly targets:

• Normal-weight women: 0.5–0.9 kg per week (approximately 2–4 kg per month) 1, 2, 3
• Underweight women: 0.5–0.9 kg per week 2, 3
• Overweight women: Less than 50% of normal rates, approximately 0.25–0.45 kg per week (1–2 kg per month) 3
• Obese women: Minimal weekly gain to achieve total pregnancy gain of 5–9 kg 2, 3

Energy Requirements to Support Weight Gain

No additional calories are needed during the first trimester unless the woman begins pregnancy with depleted body reserves. 1, 4, 2

During the second and third trimesters:

• Standard recommendation: Add 300 kcal/day above pre-pregnancy intake 1, 2, 3
• Obese women: May require only 100 kcal/day above baseline due to ample body fat stores 1
• Protein: 0.75 g/kg/day plus an additional 10 g/day throughout pregnancy 1, 2, 3

Critical Pitfalls to Avoid

Do not recommend hypocaloric diets below 1,200 calories per day, as these cause ketonemia and ketonuria, which have been associated with lower intelligence scores in offspring at ages 2–5 years. 1

Other common errors include:

• Failing to discuss weight gain expectations at the first antenatal visit, as approximately 20% of women are unaware of guidelines 1, 4
• Not adjusting recommendations for multiple gestations (twins, triplets), which require higher targets 4, 2
• Applying standard BMI-based recommendations to women with skeletal dysplasia without individualized assessment 2

Clinical Consequences of Inappropriate Weight Gain

Excessive weight gain (occurring in the majority of pregnant women) increases risk of:

• Gestational hypertension, pre-eclampsia, and gestational diabetes 4, 2
• Large-for-gestational-age babies and cesarean delivery 4
• Long-term maternal obesity and childhood obesity in offspring 4

Inadequate weight gain (affecting approximately 20% of women) increases risk of:

• Preterm birth and small-for-gestational-age infants 1, 2
• Difficulties establishing breastfeeding 3

Implementation Strategy

Begin weight monitoring at the first antenatal visit to establish baseline measurements and provide clear BMI-specific targets. 4 Use regular weight checks throughout pregnancy with automatic weight calculation tools to track progress against expected monthly gains. 4 Address psychosocial factors including negative body image and inaccurate weight perceptions that contribute to excessive gain. 4