High prevalence of vitamin D deficiency among pregnant women and their newborns in an Iranian population

Background and objective:Vitamin D deficiency during pregnancy has important health implications for the mother and infant. This study was designed to determine the prevalence of hypovitaminosis D in pregnancy and to examine the probable correlation between serum concentrations of 25-hydroxyvitamin D [25(OH)D] in maternal blood and in neonates' cord blood. As yet, few studies have examined this phenomenon in the Iranian population; thus, this research adds to a small body of literature.

Methods:Sixty-seven full-term pregnant mothers were enrolled serially from a referring general hospital in Zanjan, a province located west of Tehran. All participating mothers delivered their babies via typical vaginal delivery. Samples of maternal and cord blood were collected on the day of delivery. Serum concentrations of calcium, phosphorus, 25(OH)D and alkaline phosphatase were measured in the samples. 25(OH)D concentrations <25 nmol/L were considered to be indicative of hypovitaminosis D.

Results:Mean maternal serum 25(OH)D was 19.4 +/- 3.9 nmol/L, and cord blood 25(OH)D was 16.7 +/- 2.9 nmol/L. Hypovitaminosis D was detected in 86% of the women and in 75% of the newborns during winter and 46% of the mothers and 35% of the newborns during summer. A positive correlation was found between maternal and cord blood 25(OH)D (r = 0.55, p < 0.001).

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