Randomized open‐label trial of two weekly oral vitamin D3 supplementation regimens during the third trimester of pregnancy in Bangladeshi women: effects on maternal vitamin D status and safety

To study the potential maternal‐infant benefits of improving antenatal vitamin D status in South Asia, safe high‐dose vitamin D3 supplementation regimens need to be established. Pregnant women at 27–30 weeks gestation in Dhaka (N=28) were randomized to 70,000 IU initial dose + 35,000 IU/week vitamin D3 (A) or 14,000 IU/week vitamin D3 (B), until delivery. Baseline serum 25‐hydroxyvitamin D ([25(OH)D]) were similar in groups A (35 nmol/L) and B (31 nmol/L, P=0.34). Group A had a more robust [25(OH)D] response than B, demonstrated by several outcomes: 1) final mean [25(OH)D] was higher in A (98 nmol/L) vs. B (76 nmol/, P=0.04); 2) the modeled mean rise above baseline [25(OH)D] at steady‐state was 16 nmol/L (95% CI, 5 – 26) higher in A vs. B; and, 3) the area under the Δ [25(OH)D]‐time curve was larger in A vs. B (P=0.028). Importantly, 90% of women in group A attained [25(OH)D]>80 nmol/L at 10weeks vs. 56% in group B. Mean albumin‐adjusted serum calcium ([Ca]) and urinary calcium‐creatinine ratio (ca:cr) increased slightly after supplement initiation and then stabilized in group A; but mean [Ca] and ca:cr in groups A and B were within normal ranges and did not significantly differ between the groups in follow‐up. There were no supplement‐related serious adverse events. In this preliminary study in Bangladesh, 70,000 IU initial + 35,000 IU/week vitamin D3 in the 3 rd trimester optimized vitamin D status and was non‐hypercalcemic. Grant Funding Source : Center for Global Health, Johns Hopkins University; Department of International Health, Johns Hopkins Bloomberg School of Public Health