POSTNATAL CHANGES IN SERUM RETINOL STATUS IN VERY-LOW-BIRTH-WEIGHT INFANTS

Background: Retinol deficiency may contribute toward the development o f chronic lung disease in very low birth weight (VLBW) infants. We exa mined the retinol status during early infancy in VLBW infants from bir th to 6 weeks 'post-term'. Methods: Concentrations of serum retinol (S R) and its carrier proteins, retinol-binding protein (RBP), and transt hyretin (TTR), were determined at birth, then weekly for 8 weeks, and at 4-6 weeks 'post-term' in preterm infants of less than 34 weeks gest ation. The SR values of umbilical cord blood at birth from the preterm infants were compared to the maternal SR levels as well as to cord SR levels of term infants. Results: From 24 through 33 weeks gestation, umbilical cord SR at birth was significantly lower than, but did not c orrelate with, maternal SR (P < 0.01). The cord SR in term infants was also higher than that in preterm infants (262 +/- 68 vs. 183 +/- 67 m u g/l, P < 0.01). Longitudinal profiles of SR in 18 VLBW infants showe d that, despite regular retinol supplementation, there was a decline i n SR after birth, reaching a nadir of 128 +/- 40 mu g/l at 5-7 weeks ( P < 0.001), followed by an increase toward levels comparable to those seen in full term infants. At follow-up at the corrected age of 4-6 we eks 'post-term', SR levels in VLBW infant (222 +/- 74 mu g/l) had retu rned to within the normal range for term cord SR values. The concentra tions of RBP also showed a similar biphasic pattern. Transthyretin lev els did not change for 8 weeks but increased significantly at 4-6 week s 'post-term'. Conclusions: Current practices of retinol supplementati on in VLBW infants fail to maintain adequate retinol status in those i nfants during the neonatal period. Further efforts to improve the reti nol status in these infants should be explored.