Chronological age is the time since birth. Corrected age adjusts for prematurity by subtracting the number of weeks the baby was born early. Corrected age is commonly used to track growth and development in the early months.

Percentiles may change because of growth rate changes, measurement differences (time of day, clothing, scale accuracy), or switching between growth references such as Fenton and WHO depending on age and birth week. It is best to look at the overall trend over time rather than a single point.

Birth weight provides a starting point for comparison, especially in preterm babies using Fenton references. It can help show catch-up growth and overall progress from the beginning.

If there is a consistent drop in percentile over several measurements, very slow growth, feeding difficulties, frequent vomiting, or you simply feel something is not right, it is a good idea to consult your pediatrician or a pediatric dietitian.