Registered sonographers at Prenatal Peek help parents get a sneak peek at their babies with 3-D and 4-D ultrasounds. The 3-D images can be printed as snapshots that show realistic glimpses of the baby. What the sonographers dub "4-D" is actually a real-time video of the baby as he or she spins, stretches, and vogues for the camera. In general, staffers recommend scheduling the ultrasound between 26 and 34 weeks into pregnancy, or before 28 weeks for twins, periods at which facial features will be well developed. The team stresses that it is not a replacement for your doctor, midwife, or stork—it serves a function similar to that of a family photographer, capturing vivid images in a relaxed, professional setting.