Experiments have found that proper vitamin D supplementation for pregnant women can reduce the risk of neonatal infection with respiratory syncytial virus  Researchers tested the content of vitamin D in umbilical cord blood of 156 newborns  Among them, 54% of newborns were diagnosed with vitamin D deficiency  Among them, 12% of the children were infected with respiratory syncytial virus within one year after birth
In the above experiment, 54% of newborns' vitamin D deficiency was caused by their mothers not receiving enough vitamin D during pregnancy
 The proportion is much higher than that of children with normal vitamin D