Association between body mass index at birth and neonatal health outcomes in preterm infants: A retrospective analysis

Background: Studies on how birth body mass index (BMI) affects health outcomes in preterm infants are relatively limited.

Aim: To analyze the association between BMI at birth and neonatal health outcomes in extremely low and very low birth weight preterm infants in China.

Methods: Used data from the Chinese Premature Infant Informatization Platform (2022-2023). Preterm infants were categorized based on their birth BMI z-scores into three groups: low BMI group (< -2), normal BMI group (-2 to 2) and high BMI group (>2). The relationship between BMI and neonatal health outcomes was then analyzed.

Results: The final analysis included 1662 extremely low and very low birth weight preterm infants. The results indicated that low BMI was significantly associated with an increased risk of respiratory distress syndrome (RDS) (AOR 1.61, 95% CI 1.31-2.30), bronchopulmonary dysplasia (BPD) (AOR 1.34, 95% CI 1.00-1.80) and necrotizing enterocolitis (NEC) (AOR 1.57, 95% CI 1.01-2.42). High BMI was significantly associated with an increased risk of RDS (AOR 1.60, 95% CI 1.05-2.45).

Conclusions: BMI at birth is significantly associated with the risks of RDS, BPD and NEC in ELBW and VLBW, highlighting the importance of monitoring BMI as an additional risk predictor in a population of neonates already at high risk for adverse outcomes.