Very preterm birth: start treatment with Vitamin D (400 IU/kg/day)
Vitamin D status and response to supplementation in very preterm infants: A prospective cohort study - July 2026
Eur J Clin Nutr. 2026 Jul;80(7):694-699. doi: 10.1038/s41430-026-01746-x
Suphawe Wasuanankun 1, Prattana Rattanachamnongk 2, Buranee Yangthara 3, Sopapan Ngerncham 3, Ratchada Kitsommart 3, Punnanee Wutthigate 4
Background: Very preterm infants are at high risk of vitamin D deficiency (VDD), which contributes to metabolic bone disease (MBD) and other morbidities. Despite guidelines, optimal dosing remains uncertain. We determined VDD incidence and evaluated 25-hydroxyvitamin D [25(OH)D] responses to varying vitamin D intakes during the first 8 weeks of life.
Methods: This prospective cohort enrolled infants born at <32 weeks' gestation or birth weight <1500 g. Vitamin D supplementation followed institutional policy. Infants were categorized by total intake (parenteral plus enteral) during weeks 0-4: <400, 400-700, or >700 IU/kg/day. Serum 25(OH)D was measured at birth, 4, and 8 weeks. Biochemical markers and MBD screening were performed. VDD was defined as 25(OH)D < 20 ng/mL and excess (VDE) as >100 ng/mL.
Results: Among 126 infants (gestational age 30 [27, 31] weeks; birth weight 1230 [950, 1570] g), 94.3% had VDD at birth. At 4 weeks, VDD persisted in 17.8% receiving <400 IU/kg/day and 6.5% receiving 400-700 IU/kg/day; vitamin D excess (VDE) occurred in 3.3% and 3.2%, respectively. At 8 weeks, normal 25(OH)D was achieved in 90.1% receiving <400 IU/kg/day and 77.4% receiving 400-700 IU/kg/day, while VDE increased to 8.6% and 22.6%, respectively. Biochemical markers remained normal; only one infant developed MBD.
Conclusions: VDD is highly prevalent at birth in very preterm infants. Daily intake <400 IU/kg generally normalizes vitamin D status by 8 weeks while minimizing risk of excessive vitamin D. Higher doses may provide no additional benefit and increase risk of exceeding 25(OH)D levels.
Clinical trial registration: Thai Clinical Trials Registry. http://www.thaiclinicaltrials.org/show/TCTR20230725007 .
Related in VitaminDWiki
- Preterm births are VERY costly
- Increase infant Vitamin D: fortification, daily, weekly, monthly, breast milk - Review
- Better than Daily
- Pre-term birth costs $84,900 (vs. very little vitamin D to prevent one:
10% of births are pre-term)
Very preterm births are even more expensive
- Note: Can prevent half of preterm births
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- Reminder: Infants who have low vitamin D at birth often need more vitamin D for their entire life