Background: Low Vitamin A levels of plasma increase the risk of neonates’ morbidity. However, whether umbilical cord blood (UCB) vitamin A levels have an association with the outcomes of late-preterm infants (LPI) is not well established. This study aimed to determine umbilical cord blood vitamin A levels and their correlation with outcomes of late-preterm infants.
Methods: We prospectively studied 208 LPI between January 1, 2014，and June 30, 2015. The specimens of UCB were collected shortly after birth, and vitamin A levels were determined by Enzyme-Linked Immunosorbent Assay. All singleton newborns, with 34+0 weeks to 36+6 weeks’ gestational age, were eligible for study inclusion in the studied time intervals. Exclusion criteria included significant congenital malformations or chromosomal abnormality or congenital metabolic disease, or life-threatening disease. All subjects were implemented to follow up, and jaundice, sepsis, respiratory distress syndrome, bronchopulmonary dysplasia, necrotizing enterocolitis, death, etc. were recorded.
Results: The prevalence of low UCB vitamin A level <0.7 μmol/L was 37.5% in LPI. UCB vitamin A levels of LPI with cesarean section was lower than that with vaginal delivery (0.734 (0.634-0.796) μmol/L VS 0.904 (0.666-1.100) μmol/L P = 0.001). Additionally, binary logistic regression analysis revealed that the cesarean section was an independent risk factor for UCB vitamin A level < 0.7 μmol/L. However, UCB vitamin A levels did not correlate with gestational age, birth weight, and sex. Neonates with hospitalization or oxygen supplementation or RDS group had significantly lower UCB vitamin A levels than their counterparties ( P < 0.05), other than with hyperbilirubinemia or sepsis ( P > 0.05). However, univariate binary logistics regression analysis suggested that UCB vitamin A level < 0.7 μmol/L was not an independent risk factor for hospitalization, oxygen therapy, hyperbilirubinemia, sepsis and RDS.
Conclusions: Low umbilical cord blood vitamin A levels are common among late-preterm infants. Delivery with cesarean section is an independent risk factor for low umbilical cord blood vitamin A level. However, there is no evidence that low vitamin A level is associated with morbidity of late-preterm infants, including hyperbilirubinemia, sepsis and respiratory distress syndrome.