Neonatal outcome of small for gestational age infants born at 26-33 weeks' gestation in Chinese neonatal intensive care units

Background: Rate and outcomes of small for gestational age (SGA) infants admitted to Chinese neonatal intensive care units (NICU) has been poorly demonstrated. We aimed to describe the rate and outcomes of SGA preterm infants in Chinese NICU, and to evaluate the association of SGA status with neonatal outcomes in different gestational age (GA) and birth weight percentile groups. Methods: This cohort study included all infants born at 26-33 weeks' gestation and admitted to 25 tertiary Chinese NICUs from April 2015 to May 2018. SGA was defined as a birthweight <10th percentile for GA based on the Chinese neonatal birth weight curve. Results: A total of 24,596 infants were included, and 1,867 (7.6%) infants were SGA. SGA infants had significantly higher rates of death or any major morbidity (29.8% vs. 20.5%), mortality (7.0% vs. 4.1%), bronchopulmonary dysplasia (BPD, 17.6% vs. 9.8%), necrotizing enterocolitis (NEC, 4.8% vs. 3.2%) and sepsis (7.3% vs. 4.8%) than non-SGA infants. SGA status was independently associated with increased risk of death or any major morbidity [adjusted odds ratio: 2.37 (2.08-2.71)] as well as increased risks of death, BPD, ROP, death or BPD, death or ROP, NEC and sepsis. The increased risks of adverse outcomes for SGA infants existed across GA groups. The risks of adverse outcomes were highest among infants with a birthweight <3rd percentile. Conclusions: SGA contributes significantly to adverse neonatal outcomes. Specific attentions are warranted when caring for SGA preterm infants.