Factors that affect placental retinol transfer in preterm infants and mothers with retinol deficiency

The retinol level and retinol delivery to the placenta may vary depending on various factors involving the mother and newborn. The present study evaluates the factors affecting retinol levels in newborns and the transplacental retinol passage in preterm newborns.

In this prospective cohort study, the retinol and retinol binding protein (RBP) in the umbilical cord blood of 44 preterm infants with a gestation age of <30 weeks were studied. Serum retinol and RBP levels were determined using an enzyme-linked immunosorbent assay, and the rate of transplacental retinol passage was calculated. The demographic data of mothers and newborns, the use of vitamins by the mother, the application of antenatal corticosteroids, and any diseases diagnosed during pregnancy were recorded. An evaluation was made of the retinol, RBP, and other factors of the mother and newborn affecting transplacental retinol passage.

A retinol deficiency was identified in 68.2% of the study population. Retinol and RBP levels in umbilical cord blood (273.7 ± 150.03 ng/mL, 7.88 ± 5.6 ng/mL, respectively) were significantly higher than the corresponding levels in the mother (206.4 ± 86.26 ng/ mL, 1.04 ± 0.97 ng/mL, respectively). Umbilical cord blood retinol deficiency was more common in the male participants, while the transplacental retinol passage rate was higher in females. The umbilical cord blood RBP was found to be lower in those administered antenatal corticosteroids than in those who did not receive antenatal corticosteroids, and median maternal RBP levels were lower in patients with anemia and pregnancy-induced hypertension than in those with no disease.

Placental adaptation and contributing factors may vary in populations with severe retinol deficiency. The finding of significantly increased cord blood retinol levels when compared to maternal retinol levels in the present study suggests that some compensatory mechanisms, such as increased placental RBP levels, support the presentation of retinol to the fetus, even if the mother has a retinol deficiency.