Vitamin K in the human is made by bacteria in the gut. Since the newborn's
gut is sterile at birth it takes about a week for the bacteria to begin
producing Vit K.
The pediatric concern is bleeding but especially intercranial bleeds which
can have tragic results.Vit K is a required component in blood clotting.
Since Vit K is destroyed when give orally the the IM route is necessary (MD's
please feel free to correct me on this--I'm remembering a physiology class a
zillion years ago).
Parents have the right to refuse Vit K but I feel it must be an informed
choice.
As for the routine prophalaxis for the eyes I heard that the government
assumes all women have gonerrhea and thus the eye treatment is usually
required by state law. Other bacteria from the vaginal tract can get in the
eyes during delivery but most parents are smart enough to take the baby into
the doc if the eye(s) are all matted up. I am glad that most hospitals no
longer use Silvernitrate for eye treatment. A physician I knew got amniotic
fluid in his eyes during a delivery and used slivernitrate drops. He screamed
in pain. He was a big reason that one hospital switched to antibiotic
ointment.