Current epidemiology and factors contributing to postnatal growth restriction in very preterm infants in China

Postnatal growth restriction (PGR) is common in very preterm infants (VPIs) and is associated with adverse short and long-term developmental outcomes. Postnatal growth status for VPIs in middle- or low-income countries remains unclear. To evaluate PGR in VPIs and identify maternal and neonatal factors, clinical practice, and major neonatal morbidities associated with PGR in China. Prospective cohort study. We included 6085 infants born at <32 weeks gestation who were admitted at 57 hospitals in the Chinese Neonatal Network in 2019. Birth and discharge weights were converted to age-specific Z-scores. PGR was defined as a decrease in weight z-score from birth to discharge >2. The overall incidence of PGR was 19.9 %. The mean (standard deviation [SD]) weight Z-score was 0.12 (0.78) at birth and decreased to −1.36 (0.98) at discharge. About 4.0 % of VPIs were small for gestational age (SGA) at birth and 25.5 % of SGA infants had PGR. The incidence of PGR increased with decreasing gestational age except in the SGA subgroup. Each 1-unit increase in birthweight Z-score was associated with a 1.49-fold increased risk for PGR. Late initiation of enteral feeds and late achievement of full enteral feeds were positively associated with PGR. The common morbidities that influenced PGR were necrotizing enterocolitis ≥ stage II, patent ductus arteriosus requiring medical or surgical treatment, sepsis, bronchopulmonary dysplasia, and respiratory distress syndrome requiring surfactants. Nearly one fifth of VPIs were PGR, and one fourth of SGA had PGR, which warranted further study to investigate underlying causes by which to improve postnatal growth in very preterm infants in future. • The incidence of postnatal growth restriction in very preterm infants in Chinese NICU is 19.9%. • About 25.5% of small-for-gestational-age infants had postnatal growth restriction. • Growth outcomes in very preterm infants reflect suboptimal nutrition status. • Earlier start of enteral feeds and earlier achievement to full enteral feeds can improve postnatal growth. • Necrotizing enterocolitis is most associated with poorer postnatal growth.