Small for gestational age (SGA) means a developing baby in the womb or an infant is smaller in size than normal for the baby's gender and gestational age.
Low birth weight
Ultrasound is used to find out if a developing baby (fetus) is smaller than normal for age (intrauterine growth restriction). The most widely used definition of SGA is birth weight below the 10th percentile.
A developing baby with intrauterine growth restriction will be small in size and can have problems such as:
Carlo WA. Prematurity and intrauterine growth restriction. In: Kliegman RM, Behrman RE, Jenson HB, Stanton BF, eds. Nelson Textbook of Pediatrics. 19th ed. Philadelphia, Pa: Saunders Elsevier; 2011:chap 91.2.