Appropriate for gestational age, or AGA, describes a fetus or newborn infant whose size is within the normal range for his gestational age.

Assigning size such as SGA (small for gestational age), LGA (large for gestational age), or AGA is a way to measure and monitor the growth of the infant throughout the pregnancy as well as at the time of birth.

If a term infant is heavier than 2500 grams (about 5.5 lbs.) and lighter than about 4000 grams (about 8.75 lbs.), the baby is referred to as AGA.

Term infants over 4000 grams are referred to as LGA and those under 2500 grams are SGA.

The measurement is calculated based on the estimated gestational age (how many weeks the mother was pregnant) in comparison to what is considered normal height, weight, head size, and developmental level for a child of the same gestational age and gender.

Graphs are available showing the upper and lower normal limits for different gestational ages from the mid-20s through 42 weeks of gestation.

Knowing the group into which an infant fits is important. An AGA baby tends to have the lowest risk for any problems. AGA babies have lower rates of morbidity (disease) and mortality (death), while both LGA and SGA infants have increased rates of morbidity and mortality.