MODEL RELEASED. Pregnancy ultrasound scan. Hospital doctor using an ultrasound transducer to scan the swollen abdomen of a heavily-pregnant 28-year-old woman. The transducer emits high-frequency sound waves and detects the reflected echoes. The results (left) show the unborn child developing in its mother's uterus. This safe, and non-invasive procedure is used routinely in pregnancy to assess the growth of the developing foetus, and to detect any abnormalities.