MODEL RELEASED. Ultrasound in pregnancy. Woman in early pregnancy receives an ultrasound scan of her abdomen to monitor foetal development. The doctor (at left) moves a handheld transducer over the woman's lubricated skin, while two-dimensional images of the foetus can be seen on the screens. The foetal head appears rounded at left on screen. Ultrasound scanning is a diagnostic technique which uses high-frequency sound waves to detect body tissues of different density. In pregnancy it is performed to detect foetal disorders, and it helps establish foetal size and healthy development and hence expected delivery date. The technique is painless and safe.