The American Academy of Pediatrics recommends that all newborns receive a shot of vitamin K in the upper leg. Newborns usually have low levels of vitamin K in their bodies. This vitamin is needed for the blood to clot. Low levels of vitamin K can cause a rare but serious bleeding problem. Research shows that vitamin K shots prevent dangerous bleeding in newborns. Newborns probably feel pain when the shot is given. But afterwards babies don’t seem to have any discomfort. Since it may be uncomfortable for the baby, you may want to postpone this shot for a little while.