Which vitamin is routinely given to newborns at birth to prevent hemorrhagic disease?

• A. Vitamin A
• B. Vitamin K
• C. Vitamin C
• D. Vitamin B12

Answer: (B)

Vitamin K is given at birth to prevent hemorrhagic disease because newborns have very low stores of this vitamin and their gut is initially sterile, so they cannot rapidly synthesize it. Vitamin K is essential for activating clotting factors II, VII, IX, and X, as well as proteins C and S. Without adequate vitamin K, the coagulation cascade is impaired, increasing the risk of serious bleeding, including intracranial hemorrhage. Breast milk contains only small amounts of vitamin K, and the gut needs time to establish bacteria that produce it, so a prophylactic dose at birth rapidly replenishes stores and prevents deficiency bleeding. The other vitamins listed do not prevent this neonatal bleeding risk.