[Investigation of extrauterine growth restriction in very preterm infants in Chinese neonatal intensive care units].

Objective: To comprehensively assess the current status of extrauterine growth restriction (EUGR) in very preterm infants (VPI) and its associated factors in Chinese neonatal intensive care units (NICU). Methods: In this cohort study, 6 179 preterm infants born at <32 weeks' gestation were included, who were admitted to 57 hospitals in the China Neonatal Network in 2019 and hospitalized for ≥7 days. EUGR was evaluated by a cross-sectional definition (weight at discharge<10^th percentile for postmenstrual age), a longitudinal definition (decline in weight Z score>1 from birth to discharge), and weight growth velocity. The comparison between infants with and without EUGR was conducted by t-test, Mann-Whitney U test or χ² test as appropriate. Multivariable Logistic regression models were used to evaluate associations between EUGR with different definitions and maternal and neonatal factors, clinical practices, and neonatal morbidities. Results: A total of 6 179 VPI were enrolled in the study, with a gestational age of (29.8±1.5) weeks and birth weight of (1 365±304) g; 56.2% (3 474) of them were male. Among them, 48.4% (2 992 VPI) were cross-sectional EUGR and 74.9% (4 628 VPI) were longitudinal EUGR. Z score of weight was (0.13±0.78) at birth and decrease to (-1.35±0.99) at discharge. The weight growth velocity was 10.13 (8.42, 11.66) g/(kg·d). Multivariate Logistic regression analysis showed that among the influential factors that could be intervened after birth, late attainment of full enteral feeds (OR_adjust=1.01, 95%CI 1.01-1.02, P<0.001; OR_adjust=1.01, 95%CI 1.01-1.02, P<0.001), necrotizing enterocolitis≥Ⅱstage (OR_adjust=2.64, 95%CI 1.60-4.35, P<0.001; OR_adjust=1.62, 95%CI 1.10-2.40, P<0.001) and patent ductus arteriosus (OR_adjust=1.94, 95%CI 1.50-2.51, P<0.001; OR_adjust=1.63, 95%CI 1.29-2.06, P<0.001) were all associated with increased risks of both cross-sectional and longitudinal EUGR. In addition, late initiation of enteral feeds (OR_adjust=1.06, 95%CI 1.02-1.09, P=0.020) and respiratory distress syndrome (OR_adjust=1.45, 95%CI 1.24-1.69, P<0.001) were all associated with cross-sectional EUGR. Breast milk feeding (OR_adjust=1.33, 95%CI 1.05-1.68, P<0.001) was associated with a higher risk of longitudinal EUGR. Conclusions: The incidence of EUGR in VPI in China is high. Some modifiable risk factors provide priorities to improve postnatal growth for VPI. Nutritional management of VPI and the efforts to decrease the incidence of complications are still the focus of clinical management in China.