What is a reasonable estimate of breast milk intake for a 14-day-old, 2.1 kg, 35-week (preterm) infant, fed every 2 hours?

Feeding Volume for a 14-Day-Old, 2.1 kg, 35-Week Preterm Infant

For this 14-day-old, 2.1 kg infant born at 35 weeks gestation, provide 15-18 mL of breast milk every 2 hours (approximately 180-216 mL/kg/day total daily volume), targeting the higher end of this range to support catch-up growth and neurodevelopmental outcomes. 1, 2

Rationale for Volume Calculation

At 14 days of life, this infant is in Phase II (intermediate phase) of fluid management, where the goal is to maintain fluid and electrolyte homeostasis while regaining birth weight 1. The ESPGHAN/ESPEN/ESPR/CSPEN guidelines specify that:

• Fluid intake during Phase II should be 140-170 mL/kg/day for preterm infants to maintain sodium balance and support appropriate growth 1
• For a 2.1 kg infant: 140-170 mL/kg/day = 294-357 mL total daily volume
• Divided by 12 feeds (every 2 hours): 24.5-29.8 mL per feed

However, energy requirements must also be considered to prevent growth failure and neurodevelopmental impairment 1:

• Enterally fed preterm infants require 110-135 kcal/kg/day to match intrauterine growth rates of 17-20 g/kg/day 1
• Breast milk provides approximately 67-70 kcal/100 mL
• For 2.1 kg infant needing 110-135 kcal/kg/day: 231-283.5 kcal/day total
• This requires 330-405 mL/day of breast milk (157-193 mL/kg/day)
• Divided by 12 feeds: 27.5-33.8 mL per feed

Practical Feeding Recommendation

Start with 15-18 mL every 2 hours and advance based on tolerance 1, 2:

• This provides approximately 180-216 mL/kg/day, which balances fluid requirements (140-170 mL/kg/day) with energy needs (110-135 kcal/kg/day) 1
• Monitor for feeding intolerance (gastric residuals, abdominal distension, vomiting) 1
• Advance volume by 20-30 mL/kg/day as tolerated until reaching full enteral feeds of 150-160 mL/kg/day (approximately 315-336 mL/day or 26-28 mL per feed) 1, 2

Critical Growth Monitoring

This infant requires close surveillance for growth failure 1:

• Target weight gain: 17-20 g/kg/day (approximately 35-42 g/day for this 2.1 kg infant) to prevent dropping across weight centiles 1
• Birth weight should be regained by 7-10 days of life; at 14 days, this infant should have already regained birth weight 1, 3
• If birth weight has not been regained by day 14, pathology must be excluded and feeding regime intensified 1, 3

Sodium Supplementation Consideration

For preterm infants <35 weeks gestation during the first 2 weeks of life 1:

• Sodium supplementation of 4-5 mmol/kg/day led to better neurocognitive performance at 10-13 years compared to lower intake (1-1.5 mmol/kg/day) 1
• Ensure adequate sodium intake through breast milk or supplementation, as fluid restriction to maintain sodium balance may compromise growth 1

Common Pitfalls to Avoid

• Do not restrict fluids to <140 mL/kg/day in an attempt to prevent negative sodium balance, as this compromises energy intake and growth 1
• Do not provide excessive fluids (>200 mL/kg/day), which fails to maintain sodium balance regardless of sodium supplementation 1
• Monitor for hyperchloremic metabolic acidosis if using chloride-containing solutions; consider chloride-free sodium and potassium solutions 1
• Assess for feeding adequacy if weight gain is <17 g/kg/day, as inadequate nutrition is associated with impaired neurodevelopment and increased morbidity in preterm infants 1

Transition to Less Frequent Feeds

While 2-hourly feeds are appropriate during the early neonatal period 1, 2:

• Consider transitioning to 3-hourly feeds (8 feeds/day) as the infant matures and demonstrates consistent intake tolerance 1, 4
• This would require 37-42 mL per feed to maintain the same daily volume 4
• Do not continue frequent small-volume feeds beyond medical necessity, as this may indicate underlying feeding dysfunction 4