Study on the Current Status of Enteral Nutrition in Preterm Infants with Gestational Age < 34 Weeks in a Single-Center NICU

Objective This study aimed to explore EN status and TEN delay causes in single - center preterm infants with GA < 34 weeks.Methods A retrospective analysis was conducted on preterm infants with a gestational age < 34 weeks who were admitted to the NICU of Jingzhou Hospital Affiliated to Yangtze University from December 2019 to June 2024. These infants were divided into two groups based on their gestational age: Group A (gestational age < 32 weeks) and Group B (gestational age ≥ 32 weeks). Group A was further subdivided into Group A1 and Group A2 according to whether they achieved TEN within 21 days, while Group B was further subdivided into Group B1 and Group B2 based on whether they achieved TEN within 14 days. Statistical analyses, including independent samples t-test, rank-sum test, chi-square test, and Fisher’s exact test, were performed to compare EN-related parameters and complication rates among groups.Results During the study period, 138 cases met the inclusion criteria. After excluding 1 case, a total of 137 infants were finally included in the study. (1) Enteral feeding was initiated within 48 hours after birth in 133 cases (97.08%), and within 24 hours after birth in 64 cases (46.72%). (2) The time to achieve TEN in preterm infants with gestational ages of 26⁺⁰–27⁺⁶ weeks, 28⁺⁰–31⁺⁶ weeks, and 32⁺⁰–33⁺⁶ weeks was (42.50±22.06) days, (28.69±9.78) days, and (17.27±0.70) days, respectively. The median time to achieve TEN was 21 days in Group A and 14 days in Group B. (3) In Group A, the initial feeding volume of Group A1 (11.35 ml/kg·d) was higher than that of Group A2 (6.09 ml/kg·d), with a statistically significant difference (P<0.01); the average milk volume increase rate of Group A1 was higher than that of Group A2 in the 1st and 2nd weeks after birth, while lower than that of Group A2 in the 4th week after birth, with statistically significant differences (P<0.01). (4) In Group B, the initial feeding volume of Group B1 (15.05 ml/kg·d) was higher than that of Group B2 (12.77 ml/kg·d), with a statistically significant difference (P<0.05); the average milk volume increase rate of Group B1 was higher than that of Group B2 in the 1st and 2nd weeks after birth, while lower than that of Group B2 in the 3rd week after birth, with statistically significant differences (P<0.01). (5) Complications: In Group A, the incidence of bronchopulmonary dysplasia (BPD) in Group A1 was lower than that in Group A2, with a statistically significant difference (P<0.05), and there were no statistically significant differences in other complications; in Group B, the incidence of feeding intolerance (FI) in Group B1 was lower than that in Group B2, with a statistically significant difference (P<0.05), and there were no statistically significant differences in other complications.Conclusions Preterm infants with GA < 34 weeks often show slow feeding progression and prolonged TEN achievement. Increasing initial feeding volume and early postnatal advancement rate may shorten the TEN time and reduce BPD risk.