OBSTETRICS DOPPLER Doppler is a way of using sound waves to detect the movement of other body objects.Doppler Ultrasound is a scan used to check the movement of the blood vessels.To study the blood circulation, uterus a placenta, the doppler ultrasound scan is used.It is done in the Third(last) trimester which is between the 28th to 32nd week of the pregnancy.It takes about 30-60 minutes to perform the same.Obstetrics Doppler is safe, not causing any harm to the pregnant lady or the baby