Sex-Specific Differences in Nutrient Intake in Late Preterm Infants

Area of Science:

• Neonatology
• Pediatric Nutrition
• Infant Growth

Background:

• Preterm infants often require prescribed feeding volumes, calories, and protein via nasogastric tubes due to difficulties with oral intake.
• Existing assumptions suggest uniform nutritional needs for preterm infants once they begin ad libitum feeding, despite known sex-based differences in body composition.

Purpose of the Study:

• To investigate potential sex-specific differences in formula milk intake (volume and nutrients) among late preterm infants fed ad libitum.
• To challenge the assumption of uniform nutritional requirements in preterm infant feeding.

Main Methods:

• Retrospective analysis of 170 late preterm infants (85 male, 85 female) between 34 0/7 and 36 6/7 weeks corrected gestation.
• Inclusion criteria: appropriate for gestational age, spontaneously fed formula ad-lib, no respiratory support for ≥2 days.
• Exclusion criteria: short gut syndrome, severe chromosomal anomalies, congenital heart conditions. Data collected: sex, gestational age, birth weight, anthropometrics, maternal data, nutritional intake, neonatal morbidity.

Main Results:

• Female infants consumed significantly more formula volume (145.5 ± 20.8 mL/kg/d) compared to male infants (135.3 ± 19.3 mL/kg/d; p=0.002).
• Female infants also had higher intake of protein and calories.
• No significant difference in ad-lib feeding duration was observed between sexes, but female infants showed higher growth velocity.

Conclusions:

• This study is the first to report sex-specific differences in formula intake among late preterm infants fed ad libitum.
• Findings suggest that nutritional needs may vary by sex in this population.
• Further research is warranted to confirm these results and explore sex-specific neonatal nutrition in extremely preterm infants.