Late vitamin K deficiency bleeding after intramuscular prophylaxis at birth: a case report.

We report the case of a 6-week-old female who presented an intracranial hemorrhage due to late vitamin K deficiency bleeding (VKDB). No other evident bleeding sites were present at the moment of diagnosis. Intramuscular vitamin K (1 mg) was administered at birth. She was exclusively breast-fed. No other risk factors for VKDB were detected. Low levels of vitamin K-dependent coagulation factors and their normalization after vitamin K administration confirmed the diagnosis of late VKDB. The present case suggests potential risks related to a single dose of intramuscular vitamin K at birth.