Which complication is prevented by administering vitamin K to a newborn shortly after delivery?

Administering vitamin K to a newborn shortly after delivery primarily prevents hemorrhagic disease of the newborn. This condition, also known as Vitamin K Deficiency Bleeding (VKDB), can occur because newborns have low levels of vitamin K, which is essential for blood clotting. In utero, vitamin K does not cross the placenta effectively, and breastmilk is typically low in vitamin K. As a result, without the administration of vitamin K shortly after birth, infants are at an increased risk for uncontrolled bleeding, both internally and externally.

The introduction of vitamin K soon after birth provided through an injection allows the infant's body to create the necessary clotting factors, thus significantly reducing the likelihood of hemorrhagic complications within the first few days of life. This preventive measure is critical because VKDB can lead to serious outcomes, including severe brain injury due to bleeding or even death if left untreated.

Other complications listed, such as respiratory distress syndrome, infection, and hypoglycemia, are not directly prevented by vitamin K administration, as they involve different underlying causes and require alternative interventions.