A term baby developed jaundice on 3rd day up to the thigh with normal stool and urine. Mother's blood group is 'O' –ve and that of babies 'A' +ve. The cause of jaundice is –

Physiological jaundice Most neonates develop visible jaundice due to elevation of unconjugated bilirubin concentration during their first week. This common condition is called physiological jaundice. This pattern of hyperbilirubinemia has been classified into two functionally distinct periods - 1. Phase one Last for 5 days in term infant with peak bilirubin levels to 12 mg/dl. Last for 7 days in preterm infant with peak bilirubin levels to 15 mg/d1. 2. Phase two a. There is decline to about 2 mg/dl, which lasts for 2 weeks after which adult values are attained.