Survival without major morbidity in extremely preterm infants: a prospective multicenter study in Shenzhen, China

Due to regional and economic disparities, the current status of care for extremely preterm infants (EPIs) varies across mainland China and remains incompletely characterized. This study aimed to evaluate the survival rate and major morbidities of EPIs in Shenzhen and to identify factors associated with survival without major morbidity.

In this prospective multicenter study, clinical data of preterm infants with gestational age (GA) < 28 weeks from 21 hospitals in Shenzhen were collected between January 2022 and December 2023. Baseline characteristics, survival outcomes, and survival without major morbidity were analyzed according to seven GA groups (21-27 weeks). Morbidity analyses among surviving infants were performed using four GA groups (21-24, 25, 26, and 27 weeks). The primary outcome was survival status at discharge or at 40 weeks of postmenstrual age, and the secondary outcomes were the incidences of major morbidities.

A total of 314 EPIs were included, of whom 56 died following withdrawal of care, 24 died despite active treatment, and 234 survived, yielding an overall survival rate of 74.52% (234/314). Among all 314 EPIs, survival without major morbidity was achieved in 24.20% (76/314) of infants. Among the 234 surviving infants, the incidences of major morbidities were as follows: moderate-to-severe bronchopulmonary dysplasia (48.72%, 114/234), severe intraventricular hemorrhage and/or periventricular leukomalacia (13.25%, 31/234), necrotizing enterocolitis stage ≥ 2 (6.41%, 15/234), sepsis (22.65%, 53/234), and severe retinopathy of prematurity (42.31%, 99/234). Multivariable logistic regression analysis showed that antenatal corticosteroid (ACS) use (OR = 7.66), increasing GA (OR = 1.62), and higher birth weight (BW) (OR = 1.77) were independent protective factors for survival without major morbidity.

This prospective multicenter study provides contemporary data on survival without major morbidity among EPIs in Shenzhen. Although overall survival was relatively high, survival without major morbidity remained limited, with substantial burdens of bronchopulmonary dysplasia and retinopathy of prematurity among survivors. ACS exposure, higher GA, and greater BW were significantly associated with survival without major morbidity.