A nurse is collecting data from an infant at a well-child visit.
The nurse should expect the infant to double his birth weight by which of the following ages?

Choice A rationale

The statement “My baby will be placed under special lights if the test is elevated” indicates a need for further teaching. This statement is incorrect because phototherapy (special lights) is not used to treat phenylketonuria (PKU). PKU is a genetic disorder that results in the body’s inability to metabolize the amino acid phenylalanine. If left untreated, it can lead to intellectual disability and other serious health problems. The treatment for PKU involves a special diet that is low in phenylalanine. Therefore, the parent’s statement about using special lights for treatment indicates a misunderstanding about the nature of PKU and its treatment.

Choice B rationale

The statement “Sometimes the test is repeated in the doctor’s office at the 2-week check-up” is correct. PKU is usually diagnosed through a routine newborn screening test, and if the initial test results are positive or unclear, the test may be repeated.

Choice C rationale

The statement “My baby must take formula or breast milk before the test is done” is correct. For accurate results, the PKU test is done after the baby is 24 hours old and after the baby has had some protein in the diet.

Choice D rationale

The statement “This test checks for a genetic disorder that can be corrected by diet” is correct. PKU is a genetic disorder that can be managed with a special diet low in phenylalanine.

Choice A rationale

A set of blocks to build a block tower may not be suitable for a 7-month-old infant. At this age, infants are still developing their fine motor skills and may not have the dexterity to stack blocks effectively. Moreover, there’s a risk of the infant putting small blocks in their mouth, posing a choking hazard.

Choice B rationale

A soft toy that squeaks or crackles when squeezed is an excellent choice for a 7-month-old infant. At this age, infants are exploring their environment through touch and sound. A soft toy that makes noise when squeezed can provide sensory stimulation and help develop their grasp reflex.

Choice C rationale

A colorful rib mobile that plays music might be more suitable for younger infants. By 7 months, infants are often able to sit up and may not spend as much time lying down looking at a mobile. Additionally, they may try to pull on the mobile, posing a safety risk.

Choice D rationale

A wooden farm animal puzzle with large pieces is typically more appropriate for older toddlers who have more advanced fine motor skills and cognitive abilities. A 7-month-old infant may not have the ability to understand the concept of a puzzle.