All of the above factors increase the risk of hyperbilirubinemia in this newborn. Hyperbilirubinemia is a condition of high levels of bilirubin in the blood that can cause jaundice and brain damage.

Choice A is wrong because prematurity is a risk factor for hyperbilirubinemia, especially in babies born before 38 weeks of gestation. Premature babies have immature livers that are less able to process bilirubin and eliminate it from the body.

Choice B is wrong because breastfeeding is a risk factor for hyperbilirubinemia, particularly in some breast-fed babies who do not get enough milk or calories. Breastfeeding can also cause increased enterohepatic circulation of bilirubin, which means that bilirubin is reabsorbed from the intestines into the bloodstream instead of being excreted in the stool.

Choice C is wrong because Asian ethnicity is a risk factor for hyperbilirubinemia, as some Asian populations have higher rates of glucose-6-phosphate dehydrogenase deficiency, a genetic condition that causes red blood cells to break down more easily and release more bilirubin. Asian infants may also have lower levels of uridine diphosphate glucuronosyltransferase, an enzyme that helps convert bilirubin into a form that can be excreted by the liver.

Normal ranges for bilirubin levels vary depending on the age, weight, and health status of the newborn. Generally, bilirubin levels peak between the third and seventh day after birth and then decline gradually. The AAP recommends using a nomogram based on the infant’s age in hours and serum bilirubin level to determine the risk of severe hyperbilirubinemia and the need for treatment. Treatment options include phototherapy and exchange transfusion.