When is it necessary to supplement baby's vitamin K?
If you bottlefeed, it is not necessary to give him extra vitamin K. If you breastfeed, daily drops can be beneficial and necessary to prevent bleeding. It is important to keep using the drops until your baby reaches the age of 12 weeks at least (150 mcg).
All babies are given a dose of vitamin K shortly after birth.
Production of vitamin K
A baby's intestines do not work as well as an adult's intestines. Adults can make vitamin K themselves, which occurs in the intestines. Babies usually start regular vitamin K production at about 12 weeks.
Why is vitamin K so important?
Vitamin K is necessary for blood clotting. In the absence of vitamin K, the blood will not be able to clot properly, and in case of a wound or internal bleeding, the bleeding won't stop.
From angelababy In Q&A
From daisyrowley In Pregnancy