High prevalence of vitamin D deficiency among pregnant women and their newborns in northern India.

Background: Vitamin D deficiency is prevalent in India, a finding that is unexpected in a tropical country with abundant sunshine. Vitamin D deficiency during pregnancy has important implications for the newborn and infant. There are few data from India about the prevalence of hypovitaminosis D in pregnancy and in the newborn.

Objective: Our aim was to determine the prevalence of osteomalacia and hypovitaminosis D in pregnancy and in cord blood and to correlate maternal 25-hydroxyvitamin D [25(OH)D] status with sun exposure, daily calcium intake (dietary plus supplemental), and intact parathyroid hormone (PTH) concentrations.

Design: Serum calcium, inorganic phosphorus, 25(OH)D, heat-labile alkaline phosphatase, and PTH were studied in 207 urban and rural pregnant subjects at term. Alkaline phosphatase and 25(OH)D were measured in the cord blood of 117 newborns.

Results: Mean maternal serum 25(OH)D was 14 +/- 9.3 ng/mL, and cord blood 25(OH)D was 8.4 +/- 5.7 ng/mL. PTH rose above the normal range when 25(OH)D was <22.5 ng/mL. Eighty-four percent of women (84.3% of urban and 83.6% of rural women) had 25(OH)D values below that cutoff. Fourteen percent of the subjects had elevated alkaline phosphatase (17% of urban and 7% of rural subjects). Calcium intake was uniformly low, although higher in urban (842 +/- 459 mg/d) than in rural (549 +/- 404 mg/d) subjects (P < 0.001). Maternal serum 25(OH)D correlated positively with cord blood 25(OH)D (r = 0.79, P < 0.001) and negatively with PTH (r = -0.35, P < 0.001).

Conclusion: We observed a high prevalence of physiologically significant hypovitaminosis D among pregnant women and their newborns, the magnitude of which warrants public health intervention.