1-month-old baby cries little, sleeps a lot, when we have our next child

Patient's question:

Full term but only 3.5 pounds, didn't cry right after birth, body was purple, now has a small cry, sometimes can sleep for a whole day, sometimes doesn't sleep

Doctor's answer:

Hello, the occurrence of bruises is often caused by subcutaneous blood collection due to capillary bleeding, or it may be due to subcutaneous capillary rupture and bleeding caused by external force. It could also be possible due to fever, internal heat, capillary angioma rupture, blood diseases, etc.