Randomized controlled trial (RCT) of vitamin D supplementation in pregnancy in a population with endemic vitamin D deficiency.
What this study found
Vitamin D3 at 4000 IU/day was the most effective dose and was reported as safe, with 2000 IU/day also improving vitamin D status versus 400 IU/day. Mean serum 25(OH)D concentrations at delivery and in cord blood were significantly higher in the 2000 and 4000 IU/day groups than in the 400 IU/day group (p<0.001), and the 4000 IU/day group produced the highest levels. At delivery, 65% of mothers on 4000 IU/day were vitamin D sufficient compared with less than 10% on 400 IU/day; if a 25(OH)D threshold of >20 ng/ml was used, 91% of mothers on 4000 IU/day achieved it, and their infants were four…
- Study & population
- Double-blind randomized controlled trial in pregnant Arab women in Al Ain, United Arab Emirates, with singleton pregnancies and very high baseline vitamin D deficiency.
- Intervention
- Pregnant participants were randomized to daily oral vitamin D3 tablets plus standard prenatal vitamins, for a total vitamin D3 intake of either 400 IU/day, 2000 IU/day, or 4000 IU/day.
- Key limitation
- The trial was relatively small, single-region, and had attrition, with 30 participants discontinuing and only 126 mothers having serum 25(OH)D available at delivery.
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Open PDFOriginal abstract
BACKGROUND Vitamin D (vD) deficiency in pregnancy is a global health problem and the amount of vD supplementation to prevent vD deficiency is controversial. OBJECTIVE The objective of the study was to determine effectiveness and safety of prenatal 2000 IU and 4000 IU/d compared with 400 IU/d vD3 supplementation in a randomized controlled trial in population in which vD deficiency is endemic. DESIGN/METHODS Arab women were randomized at 12-16 weeks of gestation to 400, 2000, and 4000 IU/d vD3, which were continued to delivery. Serum 25-hydroxyvitamin D [25(OH)D] concentrations were measured during pregnancy and at delivery. The primary outcome was the maternal and cord blood 25(OH)D, and the secondary outcomes were the achievement of sufficient serum 25(OH)D of 32 ng/mL or greater (≥80 nmol/L) at delivery. SETTING The locations were primary care and tertiary perinatal care centers. RESULTS Of 192 enrolled, 162 (84%) continued to delivery. Mean serum 25(OH)D of 8.2 ng/mL (20.5 nmol/L) at enrollment was low. Mean serum 25(OH)D concentrations at delivery and in cord blood were significantly higher in the 2000 and 4000 IU than the 400 IU/d group (P < .001) and was highest in the 4000 IU/d group. The percent who achieved 25(OH)D greater than 32 ng/mL and greater than 20 ng/mL concentrations in mothers and infants was highest in 4000 IU/d group. Safety measurements were similar by group and no adverse event related to vD supplementation. CONCLUSIONS Vitamin D supplementation of 2000 and 4000 IU/d appeared safe in pregnancy, and 4000 IU/d was most effective in optimizing serum 25(OH)D concentrations in mothers and their infants. These findings could apply to other populations in which vD deficiency is endemic.