Neonatal outcome of small for gestational age preterm infants

Small for gestational age (SGA) preterm neonates (birth weight < −2 SDS) are considered to have increased risk of bronchopulmonary dysplasia (BPD) compared to appropriate for GA (AGA) neonates. It is unclear if SGA infants have increased risk for respiratory distress syndrome (RDS) and mortality. We analyzed data from 515 neonates born <30 weeks GA, 98(19%) were SGA. SGA were compared to AGA by univariate analysis and logistic regression analysis (LRA). Significant variables at univariate analysis were IUGR (67 vs 7%, p = 0.000), chorioamnionitis (1 vs 13%, p = 0.017), pre-eclampsia (62 vs 18%, p = 0.000), surfactant retreatment (47 vs 25%, p = 0.000), BPD (32 vs 20%, p = 0.015), death (30 vs 12%, p = 0.000), SatO2/FiO2 on day 3 (376 vs 433, p = 0.013), and SatO2/FiO2 ratio on day 28 (400 vs 448, p = 0.000). LRA found the following associations: regarding mortality, a decreased Sat/FiO2 ratio on day 3 (OR 1.99, 95% CI 1.26–3.16, p = 0.003); regarding BPD, surfactant retreatment (3.70, 2.11–6.49, p = 0.000), being SGA (2.69, 1.36–5.36, p = 0.005), decreasing GA (1.05, 1.03–1.08, p = 0.000), decreasing SatO2/FiO2 ratio on day 3 (1.25, 1.11–1.40, p = 0.000); and regarding severe RDS, pre-eclampsia (2.68, 1.58–4.55, p = 0.000) and decreasing GA (1.06, 1.04–1.08, p = 0.000). Conclusions: In our cohort of preterm infants, being SGA was significantly associated with BPD, but not with increased risk of mortality or RDS due to multiple pathophysiologic mechanisms.What is Known:• Small for gestational age preterm neonates are considered to have increased risk of bronchopulmonary dysplasia (BPD) compared to appropriate for GA neonates.• It is still unclear if SGA infants have increased risk for respiratory distress syndrome (RDS) and mortality.What is New:• In our cohort of 515 preterm infants (19% SGA), being SGA was significantly associated with BPD, but not with increased risk of mortality or RDS.• These results may be explained by the heterogeneity of mechanisms leading to SGA condition and by multiple mechanisms involving lung growth impairment and other factors.