Purpose of review: Although nephrogenesis in a term infant is complete, there are a number of functional changes that occur in the kidney as the infant matures. Understanding these changes will aid in the evaluation of neonates to delineate what is normal development versus a pathophysiologic problem. In addition, as many drugs are either cleared by the kidneys or can affect renal function, dosing regimens are dramatically different in the neonate as compared with the adult. These differences are greatly exaggerated in the preterm infant, making it more difficult to determine if there is a pathophysiologic problem.
Recent findings: While investigators in recent years have made great strides in understanding the early embryology of the kidney and the molecular signals involved in the formation of the kidney, there remains a paucity of functional studies. The most recent studies have re-examined the changes in the serum creatinine in the newborn and how this impacts the excretion of drugs. Developmental changes in the renal tubule transport systems and their regulation have also been more extensively studied.
Summary: The kidney undergoes many developmental physiologic changes as the neonate adapts to extra-uterine life. Understanding these changes will help in the medical management of these infants.