The effects of vitamin D supplementation during pregnancy and maternal vitamin D levels on neonatal vitamin D levels and birth parameters.

Objective: The current study aimed to measure the levels of vitamin 25(OH)D in pregnant women and in the umbilical cord blood of newborns and to evaluate the association of vitamin D levels with birth parameters.

Methods: This cross-sectional analytic investigation was performed in 100 pregnant women at term and in 100 newborns born to these mothers. Plasma vitamin D level was measured and birth parameters of the babies were recorded.

Results: Mean vitamin D levels in pregnant women and cord blood were 11.39 ± 6.24 ng/ml and 8.00 ± 4.95 ng/ml, respectively. Vitamin D levels were found to be higher in the women who had received vitamin D support during pregnancy (p < .001). Height (p = .004), head circumference (p = .003), and chest circumference (p = .005) of newborns born to mothers who had received vitamin D support were higher compared to non-receivers. Maternal vitamin D deficiency (<10 ng/ml) and insufficiency (10-30 ng/ml) was detected in 53.0% and 47.0% of the cases, respectively. None of the women had sufficient levels of vitamin D.

Conclusions: This study established that vitamin D levels were low in maternal and cord blood in spite of the administration program of Ministry of Health in pregnant women. The importance of vitamin D supplementation should be explained to the pregnant women in each visit.