Vitamin K supplementation became the norm after babies were found lacking in vitamin K, an important blood clotting factor, following birth. On day one of life, babies will have the lowest vitamin K ever. But by day 8, they will actually have the highest of any time in their life. This is one of the reasons babies are circumcised on that day. Babies were being delivered with forceps regularly, and bruising accompanied this intervention. Bruising of the brain often led to death, and the medical community thought they better do something about it (other than stop using forceps). Today, the vitamin K injection (not a vaccine) is normally given immediately after birth to avoid internal bleeding. However, it is usually not necessary, and carries its own risks, one of which is high aluminum. You can read more about the injection’s risks here.
You should know you have other options.
While it is smart to play it safe, you absolutely can decline all vitamin K legally. I would however reconsider if there were any interventions during the birth or bruising is visible on the baby. Most pediatricians will not circumcise baby without vitamin K, which is a good idea because how circumcision is done today does hold bleeding risks.
Though the injection is the only “acceptable” form of vitamin K newborn supplementation in the U.S., other countries have seen the benefits of supplementing vitamin K orally.
Here is an oral vitamin K protocol used in European countries:
Give liquid oral vitamin K to the baby directly. Not enough studies have shown that it will reach your baby through your breastmilk.
On Day One of life, supplement 2 mg of vitamin K.
Once a week (7 days from Day One), supplement 1 mg of K. Continue to supplement once per week, at 1 mg, through 12 weeks.