Study Title:

800 IU Vitamin D Is Not Enough for Pregnancy

Study Abstract

Objective: Vitamin D is essential for skeletal health, and prolonged deficiency results in infantile rickets and adult osteomalacia. The aim of the study is to determine the vitamin D status in pregnancy and to evaluate the effects of daily and of single-dose vitamin D supplementation.

Design: A prospective randomised study at St Mary's Hospital London. Patients: 180 women (Indian Asian, Middle Eastern, Black and Caucasian) were recruited at 27 weeks gestation and randomised into three treatment groups: a single oral dose of 200,000 IU vitamin D, a daily supplement of 800 IU vitamin D from 27 weeks until delivery and a no treatment group.

Measurements: Vitamin D (25-hydroxyvitamin D), parathyroid hormone (PTH) and corrected calcium levels in mothers at 27 weeks and at delivery and cord 25-hydroxyvitamin D and corrected calcium levels. Results: The final maternal 25-hydroxyvitamin D levels were significantly higher in the supplemented group (daily dose (median) 42 (IQR 31-76) nmol/l, stat dose (median 34 (IQR 30-46) nmol/l vs. median 27 (IQR 27-39) nmol/l in the no treatment; p<0.0001) and significantly fewer women with secondary hyperparathyroidism in the supplemented group (10% in daily dose vs. 12% in stat dose vs. 27% in the no treatment; p<0.05). Cord 25-hydroxyvitamin D levels were significantly higher with supplementation (daily dose median 26 (IQR 17-45) nmol/l, stat dose median 25 (IQR 18-34) nmol/l vs. median 17 (IQR 14-22) nmol/l in no treatment; p=0.001).

Conclusion: Single or daily dose improved 25-hydroxyvitamin D levels significantly. However, even with supplementation, only a small percentage of women and babies were vitamin D sufficient. Further research is required to determine the optimal timing and dosing of vitamin D in pregnancy.

Study Information

Yu CK, Sykes L, Sethi M, Teoh TG, Robinson S.
Vitamin D deficiency and supplementation during pregnancy.
Clin Endocrinol (Oxf).
2008 September

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