After the 28th week and until the end of pregnancy (ideally around the 32nd week of pregnancy), a color Doppler ultrasound examination of the fetus may be performed, which is usually referred to as 3rd trimester ultrasound. The purpose of this Doppler ultrasound is to determine the development of the fetus, while also studying the perfusion of the uterus, the placenta and the fetus itself.
This ultrasound entails biometric measurements regarding fetal growth (head circumference, abdominal circumference, femoral length, etc.), while it also estimates the amount of amniotic fluid, monitors the blood flow in fetal arteries and uterine arteries and the position and morphology of the placenta. Finally, fetal motility is also studied. The biometric measurements also provide information regarding nutrition and weight of the fetus.