The population to include in this study corresponds to the low-risk pregnant women with surveillance at the Prenatal Consultation or referenced by the Primary Care units to the Department of Obstetrics & Gynecology of Hospital de Santa Maria. The screening method for detection of fetuses at risk of fetal growth restriction currently used in low-risk pregnancies is the measurement of the symphysis-uterine distal distance at all visits from 24 weeks and a third trimester ultrasound at 30-32 (6 / 7 days weeks).