Evaluation of vitamin D supplementation doses during pregnancy in a population at high risk for deficiency

Aim/Background: Vitamin D supplementation during pregnancy is a well-accepted recommendation worldwide; however, the debate about the correct dose is ongoing. We aimed to compare daily doses of 600, 1,200, and 2,000 IU in this randomized, controlled study. Methods: The study group consisted of 91 pregnant women aged 16-42 years admitted to Kocaeli Maternity and Children Hospital between April 2011 and April 2012. The participants were randomly divided into 3 groups. 600, 1,200, and 2,000 IU/day of vitamin D was supplemented to group 1 (control group, n = 31), group 2 (n = 31), and group 3 (n = 32), respectively. Serum calcium, 25-hydroxyvitamin D (25OHD), and the calcium/creatinine ratio in spot urine samples were measured in the follow-up period. The serum calcium and 25OHD levels of the mothers' infants were measured as well. Results: The frequency of vitamin D sufficiency after supplementation was 80% in group 3 and it was significantly higher than in groups 1 (42%) and 2 (39%) (p = 0.03). The frequency of vitamin D sufficiency in the infants of the participants was 91% in group 3 and it was significantly higher than in groups 1 (36%) and 2 (52%) (p = 0.006). Conclusions: At least 2,000 IU/day of vitamin D is needed to ensure adequate vitamin D status in pregnancy and early infancy.