A nurse is evaluating the effectiveness of phototherapy for a post-term infant who has hyperbilirubinemia due to ABO incompatibility with the mother’s blood type O negative and infant’s blood type B positive.

Which of the following findings indicates that phototherapy is effective?

The newborn’s skin color is pink.This indicates that the phototherapy is effective in lowering the serum bilirubin level by transforming it into water-soluble isomers that can be eliminated without liver conjugation.

A pink skin color also means that the newborn is not jaundiced, which is a sign of high bilirubin levels.

Choice B is wrong because clay-colored stools indicate a problem with the liver or bile ducts.Bile is needed to give stools their normal brown color, and if bile is absent or blocked, the stools may become pale or clay-colored.This could be a sign of a serious condition such as biliary atresia, which is a congenital defect that causes bile ducts to be absent or malformed.

Choice C is wrong because a bilirubin level of 12 mg/dL is still high for a newborn and may require further treatment.The American Academy of Pediatrics recommends phototherapy for newborns with bilirubin levels above 15 mg/dL at 25 to 48 hours of age, 18 mg/dL at 49 to 72 hours of age, and 20 mg/dL at more than 72 hours of age.However, these thresholds may vary depending on the gestational age, risk factors, and clinical condition of the newborn.

Choice D is wrong because dark yellow urine may indicate dehydration or concentrated urine, which can increase the risk of bilirubin toxicity.Newborns receiving phototherapy should be well hydrated and have frequent wet diapers to help eliminate bilirubin from the body.Normal urine color for a newborn is pale yellow or clear.

This is because postmature babies lose the protective vernix that covers their skin in utero, and their skin becomes dry and cracked.Postmature babies also have less subcutaneous fat, which makes them look thin and wrinkled.

Choice A is wrong because postmature babies have less body fat than term babies, not more.They use up their fat stores to survive in the womb beyond 42 weeks of gestation.

Choice B is wrong because postmature babies have well-developed breast buds and areola, not flat ones.Breast development is a sign of fetal maturity that occurs around 36 weeks of gestation.

Choice C is wrong because postmature babies have less flexibility in their joints and muscles, not more.They have less amniotic fluid to cushion their movements, and their bones become more ossified as they grow older.

Normal ranges for gestational age are 37 to 42 weeks.Babies born before 37 weeks are considered preterm, and babies born after 42 weeks are considered postmature.