[Vitamin K deficiency hemorrhages in 4 exclusively breast-fed infants 4 to 6 weeks of age].

: Haemorrhages were observed in four wholly breastfed infants beyond the neonatal period. These infants were observed within a period of 8 weeks and showed the following characteristics: 1. Onset of bleedings was unexpected and without prior indication. 2. They were of a serious nature and involved the CNS in two children. 3. In all cases infants between 4 and 6 weeks of life were affected. 4. All infants had been wholly breastfed. 5. All were male. 6. There was a prompt improvement after administration of vitamin K or after blood or blood derivatives. Although preliminary own investigations do not indicate general lowering of vitamin-K-dependent coagulation factors in wholly breastfed infants in the postneonatal period, these 4 cases observed within a short time confirm the necessity to consider vitamin K deficiency in haemorrhages in infants in the postneonatal period. Diagnostic steps have to be initiated immediately.