The nurse is caring for a neonate undergoing phototherapy. What action does the nurse include on the infant's care plan?

Choice A: This is incorrect because lanugo is a fine, downy hair that covers the fetus in utero. It usually disappears by the 36th week of gestation, but it may persist in some preterm infants. Lanugo helps to retain body heat and protect the skin from amniotic fluid. Lanugo is not a sign of postmaturity, but of prematurity or intrauterine growth restriction.

Choice B: This is incorrect because a short, chubby appearance is typical of a term infant, who is born between 37 and 42 weeks of gestation. A term infant has a well-developed subcutaneous fat layer that gives them a rounded shape and smooth skin. A term infant also has a head circumference that is proportional to their body length and weight. A short, chubby appearance is not a sign of postmaturity, but of normal development.

Choice C: This is incorrect because vernix caseosa is a white, cheesy substance that covers the fetus in utero. It usually decreases by the 40th week of gestation, but it may remain in some term infants, especially in the skin folds. Vernix caseosa helps to moisturize and protect the skin from amniotic fluid and infection. Vernix caseosa is not a sign of postmaturity, but of term or near-term gestation.

Choice D: This is the correct answer because cracked, peeling skin is a common sign of postmaturity, which occurs when the infant is born after 42 weeks of gestation. A postmature infant has a loss of subcutaneous fat and water that results in dry, wrinkled, and desquamated skin. A postmature infant also has a large head circumference that is disproportionate to their body length and weight. Cracked, peeling skin indicates prolonged exposure to amniotic fluid and placental insufficiency.

Choice A: This is incorrect because weight less than the 10th percentile (SGA) means that the infant is smaller than expected for the gestational age, but not necessarily low birth weight. SGA infants may have intrauterine growth restriction due to maternal, placental, or fetal factors, but they may also be constitutionally small. SGA infants are at risk for hypoglycemia, hypothermia, polycythemia, and perinatal asphyxia.

Choice B: This is incorrect because weight greater than the 90th percentile means that the infant is larger than expected for the gestational age, but not necessarily high birth weight. Infants with weight greater than the 90th percentile are called large for gestational age (LGA) or macrosomic. LGA infants may have maternal diabetes, genetic factors, or post-term pregnancy as causes, but they may also be constitutionally large. LGA infants are at risk for birth trauma, shoulder dystocia, hypoglycemia, and respiratory distress.

Choice C: This is incorrect because weight between the 10th and 90th percentile means that the infant is appropriate for the gestational age (AGA), but not necessarily normal birth weight. AGA infants have a weight that matches their gestational age and are considered healthy and well-nourished. However, some AGA infants may have low or high birth weight depending on their gestational age at birth.

Choice D: This is the correct answer because low birth weight (LBW) is defined as a weight of 2500g or less at birth, regardless of the gestational age. LBW infants may be preterm (born before 37 weeks of gestation), term (born between 37 and 42 weeks of gestation), or post-term (born after 42 weeks of gestation). LBW infants are at risk for infection, bleeding, jaundice, and neurodevelopmental problems.