To investigate the outcomes including major complications and prognosis of extremely preterm infants with gestational age ≤25⁺⁶ weeks.

The cross-sectional study enrolled 233 extremely preterm infants with gestational age ≤25⁺⁶ weeks who were admitted to the Department of Neonatology of Shenzhen Maternity and Child Healthcare Hospital from January 2015 to December 2021. The clinical data including perinatal factors, treatments, complications, and prognosis were extracted and analyzed. These extremely preterm infants were also grouped according to gestational age and year of admission to further analyze their survival rate, major complications, causes of death, and long-term outcomes. The comparisons between the groups were performed with Chi-square test and Kruskal-Wallis.

Among these 233 extremely preterm infants, 134 (57.5%) were males and 99 (42.5%) females. The gestational age was (24.6±0.9) weeks, the birth weight was 710.0 (605.0,784.5) g, and the overall survival rate was 61.8% (144/233). Among the surviving extremely preterm infants, the earliest gestational age was 22⁺² weeks and the lowest birth weight was 390 g. There were 17.6% (41/233) of extremely preterm infants had treatment withdrawn and were discharged in line with the will of guardians. Among the rest 192 extremely preterm infants managed with aggressive treatments, 14 (7.3%) died in hospital and 34 (17.7%) had treatment withdrawn later due to severe complications. Of the 192 extremely preterm infants, 144 (75.0%) survived, and the survival rate increased year by year (χ²=26.28, P<0.001) while the mortality decreased year by year (χ²=14.09, P=0.027). Among the survivors, 20.8%(30/144) had no major complications, and the incidence of complications was also negatively related with the gestational age (χ²=7.24, P=0.044), and the length of invasive ventilation was negatively related to the gestational age (χ²=29.14, P<0.001). In the group of less than 23⁺⁶ weeks, all extremely preterm infants had one or more major complications. The follow-up were completed in 122 infants and revealed that delayed motor development, language retardation, and hearing and vision impairment accounted for 17.2% (21/122), 8.2% (10/122) and 17.2% (21/122), respectively.

Extremely preterm infants with gestational age ≤25⁺⁶ weeks are difficult to treat, but the survival rate of infants undergoing aggressive treatments increases year by year. Although the prevalence of major complications is still high, most extremely preterm infants have acceptable prognosis during follow-up.

Infant, premature; Survival rate; Prognosis; Complication