An ultrasound uses high frequency sound waves to scan an object and produce an image of it. These waves are capable of traveling though a woman's abdomen but cannot penetrate more solid objects, such as a fetus. When they reflect off the fetus the resulting echo creates a remarkably clear and accurate depiction.
Early ultrasounds were two dimensional, but today sonographers have the ability to produce three and even four dimensional images. 3D uses a process called surface rendering in which the waves are cast from different angles instead of just straight up and down. So rather than simply generating a flat 2D picture, 3D/4D ultrasound technology makes it possible to see details of the baby's limbs and facial features. 4D takes things one step further by animating a series of still 3D images to create a video.
Ultrasounds are primarily intended for medical purposes. Obstetricians use them to ensure healthy growth and absence of complications. But there is an inherent exhilaration and amazement that naturally occurs when parents see their baby moving around and hear her little heart beating. This has spawned a whole new generation of ultrasound facilities that specialize in the emotional and sentimental value these images provide.
Prenatal image studios cater to excited mothers-to-be by adding a little pomp and circumstance to baby sonograms. Friends and families are invited to come along and share in the happy moment of seeing the baby for the first time. They can even take home their own copies of images and videos to cherish forever. Considering how quickly kids grow up, it's never too early to start preserving your memories!