Vitamin K deficiency during the perinatal and infantile period

Coagulation-related plasma proteins develop slowly during the gestational p eriod and are still markedly lower than normal at birth. Great interest exi sts in the status of the vitamin K-dependent procoagulant factors (factors II, VII, IX and X) because a number of healthy newborns develop postpartum a bleeding tendency that is due to vitamin K deficiency. The most serious c ases involve intracranial bleeding with convulsions, coma and potential dea th. Typically, these infants have markedly prolonged prothrombin times that shorten following the administration of vitamin K. A common feature of the se infants is that they are breast-fed, although other factors, especially hepatobiliary diseases, contribute to this disorder. Vitamin K deficiency b leeding can develop as early as in the first 24 hours after birth, but most infants are diagnosed between days 2 and 7 postpartum. Late forms (> 1 wee k and up to 6 months) are also noted. This deficiency can be compensated fo r by prophylactically administering vitamin K to the newborns or by bottle- feeding. Although vitamin K-2 may pass in small quantities through the plac enta, it is insufficient to make up for the deficit. The first dose of vita min K can also be given orally to the newborn after one or two regular feed ings, and the second dose can be administered upon discharge from the hospi tal. A problem that remains to be solved is the late development of vitamin K deficiency in spite of prophylaxis at birth.