Physics for IGCSE & O level - Waves And Sounds (Section 6 - No. 39)
Why might ultrasound be preferred over X-rays when scanning a pregnant woman?
Ultrasound is less expensive
Ultrasound produces clearer images
Ultrasound poses less risk of harm to the baby
Ultrasound allows to scan the fetus in 3D
Explication
Ultrasound is preferred over X-rays because it causes less risk of harm to the baby.