Large for gestational age (LGA) babies are those whose birth weight lies above the 90th percentile for that gestational age. Macrosomia, also known as big baby syndrome,'s sometimes used synonymously with LGA, or's otherwise defined as a fetus that weighs above 4000 grams (8 lb 13 oz) or 4500 grams (9 lb 15 oz) regardless of gestational age. Diagnosis LGA's generally not diagnosed until after the birth, as the size and weight of the child's rarely checked during the latter stages of pregnancy.… (More on Macrosomia)