Vitamin K prophylaxis in newborns is given to prevent bleeding problems in the early neonatal period. Which statement best reflects this purpose?

• A. Newborns synthesize intestinal flora at birth
• B. Vitamin K prevents physiologic jaundice
• C. Vitamin K provides protection from infection
• D. Vitamin K prevents bleeding problems in the early neonatal period

Answer: (D)

The main idea is that giving vitamin K at birth prevents hemorrhagic disease of the newborn in the early neonatal period. Newborns have very limited stores of vitamin K and their gut is initially sterile, so they cannot synthesize enough vitamin K right away. Vitamin K is essential for activating clotting factors II, VII, IX, and X, plus proteins C and S, which helps the blood clot properly. Providing vitamin K intramuscularly at birth ensures these coagulation pathways are ready to prevent dangerous bleeding, including brain bleeds, in the first days to weeks.

This isn't about preventing physiologic jaundice or infections, and the newborn’s intestinal flora develops after birth and does not by itself prevent early bleeding. Therefore, the statement that best reflects the purpose is that vitamin K prevents bleeding problems in the early neonatal period.