Ponderal Index

BMI uses height squared; PI uses height cubed. PI more sensitive to changes in weight relative to height. PI better for very short people (children, dwarfism); BMI for adults.

Intrauterine growth restriction (IUGR) detection. Low PI = thin baby (poor nutrition in womb). Normal PI but low weight = prematurity. Helps distinguish causes of low birth weight.

Newborns: 2.2–3.0 typical. Low (< 2.0) suggests IUGR. High (> 3.5) suggests well-nourished larger baby. Track over first year; gradually lowers as child grows taller.