Most standard diagnostic obstetrical ultrasound is performed as a two-dimensional examination and is the method that is most appropriate for almost all obstetrical indications for ultrasound. This is the type of ultrasound you will usually have when necessary during the course of your pregnancy.
While useful in some diagnostic testing, three-dimensional (3D) and four-dimensional (4D) ultrasounds for obstetrical patients are most often performed without specific medical indications and often referred to as keepsake ultrasounds. Photographs and a CD/DVD of the moving images are frequently offered as an add-on to the exam. In 3D and 4D ultrasound, images are taken from different angles and through computer generated enhancement produce more detailed, life-like images of the unborn baby such as facial features, fingers, toes, and if the baby will be a boy or a girl. A 4D ultrasound takes the images produced by 3D ultrasound and also shows the baby’s movement. Most commonly, 3D and 4D ultrasounds are performed between 26 and 28 weeks of gestation. The ability to obtain clear images and activity will depend on the stage of pregnancy and the position of the fetus during the ultrasound exam. Please discuss the appropriateness and safety of 3D and 4d ultrasound before you request one.