Final answer:
An infant is expected to gain approximately 1 pound per month during the first five months of life, which aligns with the average weight doubling by six months.
Step-by-step explanation:
During the first five months of life, an infant is expected to gain approximately 1 pound per month. Following an initial weight loss after birth, an infant normally gains an average of 28 g (1 oz) per day during the first two months, which would equate to about 2 pounds per month. Later, the weight gain slows down, and on average, an infant then gains about 0.45 kg (1 lb) per month. By around six months, a healthy baby typically doubles its birth weight. This developmental milestone is important to pediatric health professionals as it helps them gauge the overall growth and development of the infant.