Comparison of the Effect of Oral Versus Parenteral Vitamin D on Serum Levels of Vitamin D in Premature Infants with Vitamin D Deficiency

Background: Vitamin D levels lower than 20 ng/mL are defined as vitamin D deficiency and levels between 20 and 30 ng/mL are defined as insufficient vitamin D. Due to the high prevalence of vitamin D deficiency in premature infants and the need for obtaining optimal treatment methods, we compared the serum levels of vitamin D before and fifteen days after administration of the drug orally and by injection. Methods: In this randomized clinical trial, 90 premature infants with gestational age < 37 weeks were admitted to NICU of Shahid Akbarabadi Hospital, with concomitant vitamin D deficiency and insufficiency entered the study and randomly received oral (with oral drops of 1,000 units daily for 15 days) or injectable (a single dose of 15,000 units intramuscularly) vitamin D supplement and followed on the 16th day after drug administration by measuring 25 (OH) D, calcium, phosphorus, and serum alkaline phosphatase (ALP). Results: In this study, the gestational age of the patients was 29.39 ± 2.42 weeks, and their average birth weight was 1,208.45 ± 238.98 grams. There was no significant difference between the two groups that received the drug, and they were similar. The level of vitamin D in premature infants suffering from vitamin D deficiency was equal to 13.20 ± 6.37 ng/dL. There was no significant difference between the serum levels of ALP, phosphorus, and calcium in the patients of the injection and oral groups before and after the intervention (P-value > 0.05). Although there was no significant difference between the serum vitamin D levels in the two groups before the intervention, its level in the oral group was significantly higher than in the injection group after the intervention (P-value = 0.006). However, none of the treatment methods independently changed the effectiveness of the treatment (P-value = 0.073). Conclusions: The results of our study showed that, in premature infants with vitamin D deficiency or insufficiency, administration of vitamin D orally or by injection significantly increases the serum concentration of 25 (OH) D3 to sufficient levels safely, and both treatment routes can be used in practice.