An appropriate for gestational age (AGA) baby is one whose size falls within the normal range for their gestational age and sex. AGA babies tend to have the lowest health risks. Gestational age can be determined through physical and neurological criteria. Small for gestational age (SGA) refers to babies smaller than the 10th percentile, while large for gestational age (LGA) means greater than the 90th percentile. Factors that influence birth weight include genetics, infections, fetal growth issues, and maternal health behaviors and characteristics. Complications for SGA infants include respiratory issues and infections, while LGA babies face risks like shoulder dystocia and hypoglycemia. Gestational age and fetal growth are