This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Pediatrics
Feature of hemorrhagic disease of new born is ? 
Select and explain. 
A. Prolonged prothrombin time, B. Defective platelet count, C. Prolonged bleeding time, D. Prolonged thrombin time
A: Prolonged prothrombin time
Answer: A: Prolonged prothrombin time 
Explanation: Ans. is 'a' i.e., Prolonged prothrombine timeo Normal new borns are moderately deficient in vitamin K.o This deficiency increases on 3'd 51h day when, vitamin K level falls fuher. The serum level of vitamin K stas increasing from 13th to 15th day of life and achieves adult level at 3 months.o This is normal, and does not produce any bleeding.o In hemorrhagic disease of the newborn there is delay in achieving the normal vitamin K level. Clinical Featureso Vitamin K deficiency produces severe bleeding.o Bleeding occurs from umbilical cord stump on 2"d/3rd day after bih.o Intracranial bleding and large intramuscular hemorrhages may occur.o Increased prothrombin time and increased paial thromboplastin time.T/To Parenteral vitamin K therapy.