[A comparative analysis of the efficacy of two vitamin D supplementation regimens in preterm infants: a prospective randomized controlled study].

Objective: To study the effect of different vitamin D supplementation regimens on the nutritional status of vitamin D on day 28 after birth in preterm infants with a gestational age of <34 weeks.

Methods: A total of 59 preterm infants with a gestational age of <34 weeks who were born from October 2018 to October 2019 were enrolled and divided into an observation group with 30 infants and a control group with 29 infants. The infants in the observation group received a single-dose intramuscular injection of vitamin D (10 000 IU/kg), while those in the control group received oral vitamin D drops (900 IU/d) for 25 days. Venous blood samples were collected within 48 hours after birth (before vitamin D supplementation) and on day 28 after birth to measure the serum 25-hydroxyvitamin D [25(OH)D] level.

Results: Within 48 hours after birth, the prevalence rate of vitamin D deficiency (≤15 ng/mL) was 78% among the 59 preterm infants. There were no significant differences in the serum 25(OH)D level and the prevalence rate of vitamin D deficiency between the two groups (P>0.05). Compared with the control group on day 28 after birth, the observation group had a significantly higher serum 25(OH)D level (P<0.05) and a significantly lower prevalence rate of vitamin D deficiency (P<0.05). There were no cases of vitamin D overdose or poisoning.

Conclusions: In preterm infants with a gestational age of <34 weeks, single-dose intramuscular injection of 10 000 IU/kg vitamin D can significantly increase serum 25(OH)D level on day 28 after birth and safely and effectively reduce the prevalence rate of vitamin D deficiency.