Details.
A trained technician applies gel to the abdomen and uses a transducer to create images and take measurements for medical analysis. Images can be viewed on a flat screen TV by the patient and partner. An early pregnancy ultrasound may also involve a transvaginal ultrasound using a small probe to capture more detailed images. Prenatal ultrasounds between 11 and 40 weeks require no preparation or full bladder. Ultrasounds before 11 weeks require drinking 250 ml to 750 ml of water one hour before the appointment and not urinating.