Comparison of Vitamin D Levels in Premature Infants with and without Retinopathy of Prematurity

Retinopathy of prematurity (RoP) is a cause of newborn blindness. Several predisposing factors have been reported to contribute to the disease process. The current study aimed to compare serum vitamin D levels in infants with and without RoP.

This case-control study was conducted on 154 very low birth weight (VLBW) infants admitted to Ghaem hospital, Mashhad, Iran, during 2016–2019. Retinal examination for RoP was done at the 32nd week of pregnancy and vitamin D level was determined using the infants’ first-day serum samples. A researcher-made questionnaire including maternal, infant, laboratory, and retinal examination information was used as the data collection tool.

Out of 154 infants in the study, 56 (36.4%) were normal while 98 (63.6%) had RoP. Based on the severity of retinopathy, 43 infants (43.9%) were at stage I, 48 (49%) at stage II, and 7 (7.1%) at stage III. Significant differences in neonatal (P<0.001) and maternal (P=0.015) vitamin D levels, first and fifth minute Apgar scores (P=0.034 and P=0.001, respectively), and weight (P=0.014) were found between the infants with and without RoP.

The incidence of RoP was higher in infants with lower gestational age, lower birth weight, low first and fifth minutes Apgar scores, and male sex. Low serum levels of vitamin D in premature infants and their mothers were associated with incidence of RoP. The higher the stage of RoP, the greater was the severity of vitamin D deficiency. Thus, controlling the maternal vitamin D level during pregnancy, consumption of vitamin D supplements, and investigation of serum vitamin D levels in premature infants are recommended. Early correction of vitamin D deficiency may lead to reduction of RoP.