What hormonal changes occur in an infant when transitioning from fetal to neonatal state?

• A. High insulin and low glucagon
• B. Low insulin and high glucagon
• C. No changes in hormone levels
• D. High cortisol and low catecholamines

Answer: (B)

In the transition from fetal to neonatal life, significant hormonal changes occur, particularly in the regulation of blood glucose. During the fetal period, the placenta provides glucose, and insulin levels are relatively high in the fetus to manage this supply. However, once the infant is born and begins to rely on its own metabolic processes, there is a notable decrease in insulin levels, coupled with an increase in glucagon.

This shift is crucial for the newborn as it needs to establish its own blood glucose homeostasis outside of the womb. High glucagon levels facilitate the mobilization of stored energy substrates, which is vital as the infant begins feeding and adjusting to life outside the maternal environment. The low insulin and high glucagon profile ensures that the infant can effectively respond to the new challenges of maintaining adequate blood glucose levels, especially after the initial period of feeding.

In this context, the other choices do not accurately reflect the physiological changes taking place. Hormonal changes are indeed significant, so the notion of no changes in hormone levels is incorrect. High insulin levels would not support the infant's metabolic needs following birth, and while cortisol plays a role in the transition process, the emphasis here is primarily on the insulin and glucagon balance rather than cortisol and catecholamines respectively.