A nurse is reinforcing teaching about car safety with the parents of a preschool-age child.
Which of the following findings indicates the correct use of a booster seat?

Choice A rationale

The infant's birth weight typically doubles by 4-6 months and triples by 1 year of age. If an infant's weight has tripled at 6 months, it may indicate overnutrition or an underlying health condition.

Choice B rationale

Lateral incisors usually appear between 9 to 13 months. At 6 months, the central incisors are more likely to be emerging.

Choice C rationale

The posterior fontanel typically closes by 2 to 3 months of age. Therefore, by 6 months, it is expected to be closed.

Choice D rationale

Infants usually sit without support around 8 months. At 6 months, they may sit with support or briefly without support but not consistently.

Choice A rationale

Infants typically do not double their birth weight by 2-3 months. This milestone is more commonly reached slightly later in infancy.

Choice B rationale

By 5-6 months, many infants double their birth weight, indicating healthy growth and development. This timeline aligns with common pediatric growth patterns.

Choice C rationale

While growth continues at a steady pace, most infants have already doubled their birth weight before reaching 9 months. This age generally marks further physical and developmental milestones.

Choice D rationale

By 12 months, infants have typically more than doubled their birth weight. This age is associated with continued growth, development, and new milestones.