MODEL RELEASED. Pregnancy ultrasound. Surprised doctor carrying out an ultrasound scan of a pregnant woman's swollen uterus (womb). A device called a transducer (in hand, centre) is moved over the patient's abdomen. It emits very-high- frequency sound waves and detects the reflected echoes. The results are used to build an image of the unborn child in the womb, as seen on the monitor (upper centre). This safe, non-invasive procedure is used routinely in pregnancy to assess the growth and health of the developing foetus and to detect any abnormalities.