Aim: To evaluate vitamin D (vitD) monitored therapy effectiveness and safety in preterm neonates.
Patients and methods: Our observational study was carried out in 80 neonates born before 33 weeks' gestational age (GA) hospitalized in the Clinical Department of Neonatology and Neonatal and Intensive Care Department Medical University of Warsaw from July 2013 to July 2014. Daily vitamin D oral supplementation was provided from 1 to 3 weeks of age at the dose of 500-1000 IU/24 h. The dosage was modified according of 25-hydroxyvitamin-D blood serum concentration. Both blood serum 25(OH) D concentration and calcium-phosphate metabolism were assessed at 4 weeks of age, at 34-37 weeks' post-conceptual age (on discharge) and at 39-41 weeks PCA.
Results: Mean serum 25(OH)D level was 40 ng/ml at 4 weeks of age, 61 ng/ml at 34-37 weeks PCA, and 53 ng/ml at 39-41 weeks PCA. Higher concentrations were observed in ELBW neonates. Deficiency was noted most often at the first measurement. 52.5% of neonates received 500IU vitD before discharge, 19% had stopped supplementation due to overdosing. High dose vitD supplementation was provided in 34% cases. Disturbance of calcium-phosphate metabolism due to vitD deficiency was observed in one patient. Hypervitaminosis was associated with higher calcium-creatinine ratio. Very high individual heterogeneity of 25(OH)D concentration changes were observed (from 70 ng/ml/4 weeks decrease to 92 ng/ml/4 weeks increase).
Conclusions: Supplementation of vitamin D in preterm neonates needs monitoring. A safe time interval to monitor vitamin D supplementation seems to be 1 month. The schedule of the therapy requires further studies.