Like regular ultrasounds, 3D and 4D ultrasounds use sound waves to create an image of your baby in your womb. What’s different is that 3D ultrasounds create a three-dimensional image of your baby, while 4D ultrasounds create a live video effect, like a movie — you can watch your baby smile or yawn.

Parents often want 3D and 4D ultrasounds. They let you see your baby’s face for the first time.

Keep in mind that 3D and 4D ultrasounds are not typically used to diagnose problems with your baby. Also, getting an ultrasound at a commercial center is not a substitute for medical care.