Regulation of fetal growth is complex and still poorly understood. It involves genetic, nutritional, environmental, placental, hormonal and fetal factors. Weight of the child at birth is critical determinant of neonatal morbidity and mortality and the risk of metabolic diseases throughout the life span. Contributing fetal factors for low birth weight are multifaceted and include factors such as: maternal age, poor fetal genome, fetal infections, hormones, fetal malformations, multiple fetuses, amino acids, glucose, lipids. Risk factors for macrosomia are maternal diabetes, high pre- pregnancy BMI, excessive weight gain during pregnancy, multiparity, parental height, prolonged gestation. Nutritional insult during a critical period of gestation may leave permanent ‘memory’ throughout life. Early antenatal screening for chromosomal abnormalities and congenital malformations will ensure continuation of healthy pregnancy.

Keywords: Fetus; Low Birth Weight; Macrosomia; Genetic; Fetal Infections; Malformations.