Abstract:

Objective To investigate the effect of different delayed cord clamping methods on extremely preterm infants at < 28 weeks of gestation. Methods Extremely preterm infants who were born less then 28 weeks of gestation from January 2019 to December 2020 in the Neonatology Department of Shenzhen Maternity and Child Healthcare Hospital Affiliated to Southern Medical University were retrospectively included and divided into conventional group，delayed cord clamping group，and severed cord for cord extrusion group according to the type of umbilical cord clamping. The time spent on invasive assisted ventilation，time spent on noninvasive assisted ventilation，length of stay，frequency of blood transfusions，and incidence of periventricular⁃intraventricular hemor⁃ rhage，necrotizing enterocolitis，late ⁃ onset sepsis，respiratory distress syndrome，bronchopulmonary dysplasia， and retinopathy of prematurity during hospitalization were compared among these three groups of infants. Results The infants in the delayed cord clamping group and the extruded cord group spent less time on invasive and nonin⁃ vasive assisted ventilation and had a shorter hospital stay than those of the conventional group；the frequency of blood transfusion and the incidence of periventricular ⁃intraventricular hemorrhage，respiratory distress syndrome， bronchopulmonary dysplasia，and retinopathy of prematurity were lower than those in the conventional group，and there were statistically significant differences（P < 0.05）；The infants in the delayed cord clamping group and the extruded cord group spent less time on invasive and noninvasive assisted ventilation and had a shorter hospital stay than the those of the conventional group；the frequency of blood transfusion and the incidence of periventricular⁃ intraventricular hemorrhage，respiratory distress syndrome，bronchopulmonary dysplasia，and retinopathy of prema⁃ turity were lower than those in the conventional group，and the differences were statistically significant（P < 0.05）. Conclusion Both methods，delayed cord clamping and severed cord with extrusion，shorten the time of invasive assisted ventilation and noninvasive assisted ventilation in extremely preterm infants，shorten the period of the hospital stay，reduced the frequent blood transfusions during hospitalization，and reduced the incidence of periven⁃ tricular ⁃intraventricular hemorrhage，respiratory distress syndrome，bronchopulmonary dysplasia，and retinopathy of prematurity in extremely preterm infants.

Key words:

delayed cord clamping, umbilical cord, ligation, extremely preterm infant