Final answer:
A healthy infant typically doubles their birth weight by six months and triples it by one year, with the birth height increasing about 1 inch each month for the first six months. The anterior fontanel closes between nine to 18 months after birth, and by 12 months, the chest circumference is generally larger than the head circumference.
Step-by-step explanation:
In evaluating an infant's physical status and growth, certain expectations are established based on average growth patterns. It is generally expected that a healthy infant will double their birth weight by six months and triple their birth weight by 12 months. Additionally, growth in length is quite rapid, with an average of 2.5 cm (1 inch) per month during the first six months and about 1.2 cm (0.5 inch) per month during the second six months. Hence, an infant's birth height does increase approximately 1 inch each month for the first six months. The anterior fontanel, which is the soft spot on the top of a baby's head, is expected to close between nine to 18 months after birth, not 4 to 8 weeks. By the age of 12 months, it is usual for an infant's head circumference to be smaller than their chest circumference.