Deficiency Causes fat malabsorption neonates have sterile intestines and are unable to synthesize vitamin K aggravated by mothers who took anticonvulsants during pregnancy neonates are given vitamin K injection at birth to prevent hemorrhage newborns are unable to produce enough vitamin K due to a sterile gut can also occur after prolonged use of broad-spectrum antibiotics destruction of normal gut flora ↓ in hepatic function can ↓ vitamin K activation Presentation ↑ PT and ↑ aPTT but normal bleeding time easy bruising, bleeding hemorrhagic disease of the newborn Excess Presentation hemolytic anemia and jaundice