Study On Vitamin A Levels In Preterm Infants And Its Influencing Factors And Respiratory Outcomes

Objective:To study the early postnatal serum vitamin A（VA）levels of preterm infants,analyze the major perinatal factors contributing to vitamin A deficiency in preterm infants,and explore the impact of serum vitamin A levels on respiratory outcomes,other preterm complications,and clinical respiratory therapy in preterm infants.Methods:Premature infants born from January 2021 to September 2022 and admitted to the neonatal intensive care unit of Dalian Women and Children’s Medical Group were inclusion,trace venous blood was collected within 24 hours after birth,serum vitamin A levels were determined by high performance liquid chromatography fluorescence detection,and they were divided into vitamin A severe deficiency group（VA<0.1 mg/L）,vitamin A deficiency group（0.1 mg/L≤VA<0.2 mg/L）and non-vitamin A deficiency group（VA≥0.2 mg/L）according to vitamin A levels.Information related to the three groups of preterm infants was collected[including birth gestational age,birth weight,sex,Apgar score（1 min,5 min）];Maternal data[maternal age,number of pregnancy,number of delivery,method of delivery,mode of pregnancy,premature rupture of membranes,gestational comorbidities（including gestational hypertension,gestational diabetes and abnormal thyroid function）,antenatal corticosteroids];Clinical outcomes in preterm infants include neonatal respiratory distress syndrome（RDS）,pneumonia,bronchopulmonary dysplasia（BPD）,wet lung,pulmonary hemorrhage,asphyxia,neonatal sepsis,necrotizing enterocolitis（NEC）,anemia,intracranial hemorrhage,and hypoglycemia;Clinical respiratory treatment including mechanical ventilation and duration,noninvasive ventilation and duration,low-flow oxygenation and time,caffeine usage time,treatment of pulmonary surfactant（PS）,and hospital length of stay,analysis and comparison of preterm infants and maternal factors,postnatal clinical outcomes and respiratory therapy between groups,and a multifactorial logistic analysis was performed to explore the factors influencing vitamin A deficiency and its correlation with respiratory outcomes and other clinical disorders.Results:A total of 202 preterm infants(28 weeks≤gestational age≤36⁺⁶ weeks)were included in the study,with a mean gestational age of M=33.8 weeks,an average birth weight of（2082.5±526.3）g,and an average vitamin A level of（0.15±0.05）mg/L.There was no statistically significant difference between the three groups of preterm infants in terms of sex,methods of pregnancy,Apgar score（1 minute,5 minutes）,and maternal body weight index,gestational comorbidities（gestational hypertension,gestational diabetes,abnormal thyroid function）,and antenatal corticosteroids application（P>0.05）.The overall serum vitamin A deficiency rate of preterm infants was 78.7%,of which the severe vitamin A deficiency rate and vitamin A deficiency rate were 15.3%and63.4%separately,and the serum vitamin A levels were negatively correlated with gestational age and birth weight,the difference was statically significant（P<0.05）.The gestational age,birth weight,twin pregnancy,cesarean section and pneumonia incidence of preterm infants in the vitamin A severe deficiency group and vitamin A deficiency group were higher than those in the non-vitamin A deficiency group,while the maternal age,premature rupture of membranes,the incidence of BPD,the length of hospitalization and using caffeine were significantly lower than those in the non-vitamin A deficiency group（P<0.05）.Spearman correlation test analysis found that the incidence of pneumonia and the risk of using mechanical ventilation in preterm infants increased with lower vitamin A levels（P<0.05）.Multifactorial regression analysis showed that twin,cesarean section,middle and late preterm infants（relative to early preterm births）were risk factors for vitamin A deficiency,and advanced maternal age was a protective factor for vitamin A deficiency;Small gestational age and vitamin A deficiency was a high-risk factor for the occurrence of RDS;The high risk factors for the development of BPD in premature infants are smaller gestational age,lower birth weight,and long duration of mechanical ventilation.Conclusion:Vitamin A deficiency is prevalent in premature infants after birth and is more likely to occur in preterm infants delivered at older birth gestational age,younger maternal age,twin pregnancies,and cesarean section.Preterm infants of small gestational age,low birth weight,and longer duration of mechanical ventilation are at increased risk of BPD,resulting in longer length of hospitalization and longer caffeine usage time.There is a correlation between serum vitamin A levels and RDS,pneumonia and mechanical ventilation in preterm infants,and vitamin A deficiency increases the risk of RDS,pneumonia and the use of mechanical ventilation.Therefore,monitoring of vitamin A levels in preterm infants should be strengthened to avoid adverse outcomes.