Prenatal detection and consequences of fetal macrosomia.

Macrosomia is diagnosed when excessive intrauterine fetal growth occurs and the birth weight surpasses an established limit. The causes and risk factors for fetal macrosomia are diverse. Pregnancies with fetal macrosomia are considered high risk and require intensive antenatal care. Prenatal ultrasound appears to be the best method for performing weight estimates before birth, as the correct birth weight is often underestimated when using biometric formulae to determine the fetal weight. Three-dimensional volume sonography has been shown to improve estimates of fetal weight by including limbs volumes. The recent Hart formula has been specifically developed for fetal macrosomia estimation and appears to improve accuracy. Delivery of a macrosomic baby is also high risk and should be performed in tertiary centres with experienced obstetricians.