The effect of formula versus breast feeding and exogenous vitamin K1 supplementation on circulating levels of vitamin K1 and vitamin K-dependent clotting factors in newborns

Abstract

The influence of breast or formula feeding together with that of a single supplementation of vitamin K1 at birth, on the vitamin K1 level and vitamin K-dependent clotting factors were studied in 65 breast and 15 formula fed infants. All breast fed newborns without supplementation (n = 25) had very low serum vitamin K1 at weeks 1 and 6. Oral vitamin K supplementation (n = 22) or i.m. (n = 18) at birth resulted in high serum levels at week 1, while at week 6 the effect had disappeared. Formula fed infants had vitamin K1 values within the normal adult range at all study points. The low serum levels of vitamin K1 were not associated with haemorrhagic disorders or coagulation abnormalities. The mean values of vitamin K1 in maternal sera at weeks 1 and 6 were 2.3 nmol/l and 1.8 nmol/l and in breast milk 2.7 nmol/l and 2.0 nmol/l respectively. No correlation existed between the values in breast milk and maternal serum. To maintain serum levels of vitamin K1 within the adult physiological range, repeated administration of low doses is needed in breast fed newborns beyond 1 week of age.