Maternal Vitamin D in the Late First and Second Trimester is Beneficial for Healthy Development of Fetal Head Circumference

Background: We previously showed that vitamin D supplementation might ameliorate typical clinical symptoms in children with autism spectrum disorder. In this study we examined the effects of maternal vitamin D status during pregnancy on the development of the fetus. Methods: Seventy-eight healthy Japanese women with uncomplicated pregnancies were enrolled in the study. Urine 25-hydroxy vitamin D (25OHD) and creatinine were measured. 25OHD concentrations were normalized for creatinine (ng/mg creatinine). Newborn anthropometry (height (cm), head circumference (cm), chest circumference (cm) and birth weight (kg)) of babies delivered naturally were measured and the relationship with the urinary vitamin D concentration of the mother at less than 90 days (third trimester) to delivery and more than 90 days to delivery (late first to second trimester) was examined. PC12 cells with various neurobiological processes were cultured and differentiation induced by 25OHD enhanced nerve growth factor was assessed. Results: Maternal and newborn characteristics were not significantly different between the late first and third trimesters. The associations between newborn length, chest circumference, birth weight and the urinary 25OHD concentration of mother in the late first and second trimester and the third trimester were not significant. As lightly positive association between urinary 25OHD and head circumference was observed in the late first and second trimester (r= 0.309), but not in the third trimester. Six nmol/L of 25OHD (=1/5 of serum level) enhanced nerve growth factor induced differentiation in PC12 cells. Conclusion: These findings show that vitamin D supplementation in the late first and second trimester beneficial for the healthy development of the fetal head circumference and neural system.