Obstetric ultrasound (or sonogram) is the use of sound waves to create images of your baby while still inside the uterus. It can be performed across the abdomen or from a vaginal approach. 3D images can be created by taking a series of images in thin slices and using a computer to assemble the images into a 3D picture of the baby. A series of 3D images can be collected to create a “movie” that demonstrates the baby’s movements in 3D. This is referred to as dynamic 3D or more commonly as 4D ultrasound.
Although 3D/4D ultrasound can be performed at any point in the pregnancy, 26 to 30 weeks may be a good time given the size of the baby, and the volume of amniotic fluid around the baby. Ultrasound sessions include still printed images as well as brief videos on DVD.
Good 3D images can be very impressive and may be useful to evaluate congenital anomalies including spina bifida, cleft lip and polydactyl. However, most insurance companies do not cover 3D/4D ultrasounds. As a result, 3D/4D ultrasound is usually performed to enhance bonding with the baby and for entertainment purposes.