Vitamin D status in Chinese pregnant women and their newborns in Beijing and their relationships to birth size

Objective: To evaluate the prevalence of vitamin D deficiency in pregnant women and their newborns in Beijing, China and the influence of vitamin D deficiency on birth size. Design: A cross-sectional study. Setting: Data were collected from pregnant women who delivered during April to May 2010 at 306 Hospital of PLA in Beijing, China. Subjects: Participants in the study were seventy healthy nulliparous pregnant women with singleton pregnancies who delivered healthy babies at full term and their newborns. Results: Severe vitamin D deficiency (25-hydroxyvitamin D (25(OH)D) < 25 nmol/l) was detected in 54.5% of mothers and 46.6% of newborns. Neither mothers nor newborns had serum 25(OH) D concentrations that reached the normal level (>75nmol/l). The concentration of 25(OH) D in mothers was positively correlated with that in cord blood (r = 0.89, P < 0.001). Newborns of mothers with severe vitamin D deficiency had lower birth length and birth weight. The head circumference and birth weight were lower in vitamin D-deficient newborns. Conclusions: The study indicates that pregnant women and neonates residing in Beijing are at high risk of vitamin D deficiency. Neonatal 25(OH) D concentrations are dependently related to maternal 25(OH) D levels. Maternal and neonatal vitamin D status influences newborn size.