Due to low placental transfer of vitamin K, a sterile gut, and immature liver, infants are born with low concentrations of vitamin K (122, 123)
Cyanocobalamin is distributed into breast milk in amounts similar to those in maternal plasma, and distribution in breast milk allows for adequate intakes of cyanocobalamin by breast-feeding infants
Increased energy levels: This is the benefit I hear about most often
[17] Physiologic B12 requirements increase during gestation, and parenteral cyanocobalamin is considered appropriate when dietary intake or intestinal absorption is inadequate
So I figured he was probably super anemic, was not eating and needed to build his blood back up
Currently, no universally accepted treatment guidelines exist, and management strategies are often symptomatic