Final answer:
It is true that small-for-gestational-age infants have low glycogen stores, and large-for-gestational-age infants are prone to hyperinsulinemia. The former is due to intrauterine growth restriction, often linked to maternal undernutrition, while the latter can result from excessive maternal glucose and the infant's resulting overproduction of insulin.
Step-by-step explanation:
Understanding Birth Weight and Infant Nutrition
The initial statement that small-for-gestational-age infants have low glycogen stores is generally true. These infants have experienced intrauterine growth restriction, often due to maternal undernutrition, which can result in compromised nutrient stores such as glycogen. Glycogen is the stored form of glucose, which is critical for maintaining normal blood glucose levels, especially in newborns.
Concerning large-for-gestational-age infants, who weigh more than the 90th percentile for their gestational age, it is also true that they are prone to hyperinsulinemia. This condition is where there is too much insulin in the blood relative to the level of glucose. The presence of excess insulin is often a response to high blood glucose levels, as insulin facilitates the transport of glucose into the cells where it can be stored as glycogen or converted into fatty acids and stored as fat. This mechanism frequently occurs in infants of diabetic mothers because the fetal pancreas produces extra insulin in response to high maternal glucose levels.
Consequently, the presence of hyperinsulinemia can lead to an increased rate of glucose uptake by the infant's tissues and a subsequent drop in blood glucose levels (hypoglycemia) after birth. This phenomenon is seen in various glycogen storage diseases and conditions that affect carbohydrate metabolism.