Newborns are relatively<unk> <unk>  deficient for a variety of reasons: They have low<unk> <unk>  stores at birth as<unk> <unk>  passes the placenta poorly. Levels of<unk> <unk>  in human breast milk are low. Gut flora, that in adults produces<unk> <unk> , has not yet developed. Early<unk>  is rare and caused by maternal medications that interact with<unk> <unk>  such as warfarin, phenytoin, or rifampicin. Classical<unk>  is more common and caused by the relative<unk>  at birth with inadequate<unk> <unk>  intake. This is often termed idiopathic as no one cause is found. Late<unk>  presents after day 8 and up to 6 months of age, coinciding with the typical age for exclusive breast feeding due to the low levels of<unk> <unk>  in human breast milk. Many of these infants have poor<unk> <unk>  absorption due to cholestasis which compounds low intake.
Vitamin K deficiency bleeding
Contaminated haemophilia blood products
Venom-induced consumption coagulopathy
Cold autoimmune hemolytic anemia
Quebec platelet disorder
Acquired haemophilia
Postcoital bleeding
Thrombophilia