HDN is categorized into three types based on the timing of onset:
Early HDN: Occurs within the first 24 hours of life, often associated with maternal use of medications that inhibit vitamin K. Classical HDN: Occurs between 1 to 7 days of life, typically in breastfed infants who do not receive vitamin K prophylaxis. Late HDN: Occurs between 2 weeks to 6 months of life, primarily in exclusively breastfed infants with no vitamin K supplementation.
