Pounds per square inch. The pound per square inch or, more accurately, pound-force per square inch (symbol: lbf/in2; abbreviation: psi) is a unit of pressure or of stress based on avoirdupois units. It is the pressure resulting from a force of one pound-force applied to an area of one square inch:
small for gesÂ·taÂ·tionÂ·al age. Infant whose birth weight is below the tenth percentile for gestational age. small for gestational age. SGA. 1. Term describing an infant whose birth weight is at or below the 10th percentile, as correlated with the number of weeks in utero on the intrauterine growth chart.
Very Low Birthweight. Very low birthweight is a term used to describe babies who are born weighing less than 1,500 grams (3 pounds, 4 ounces). Only a few babies, 1.5%, are born this tiny. However, the overall rate of very low birthweight babies in the U.S. is increasing. This is primarily due to the greater numbers of multiple birth babies who are more likely to be born early and weigh less. Babies with very low birthweight look much smaller than other babies of normal birthweight.