Diagnostic ultrasounds are standard and ubiquitous during pregnancies. Your doctor will typically order an ultrasound at least twice during your pregnancy. The initial ultrasound is usually part of a screening procedure and serves as an additional confirmation of the pregnancy and due date. Later in your pregnancy, the second ultrasound will tell you your baby's gender and screen for specific health issues.
In most cases, your doctor will utilize a 2D ultrasound for both of these tests. However, you may have also heard about 3D and 4D ultrasounds. Keep reading if you've been wondering why your doctor doesn't order more of these seemingly more advanced tests.
What's the Difference?
Ultrasounds work by bouncing soundwaves off of structures in your body and recording the return (or "echo"). Since these soundwaves return at different rates based on the depth or composition of a structure, the ultrasound machine or operator must adjust the results to achieve the desired image. This approach ultimately produces a two-dimensional "slice" image of your body (and baby).
3D and 4D ultrasounds work on the same principle, but they take additional "slices" to provide more detail. A 3D ultrasound takes multiple two-dimensional slices at different depths and joins them together to form an image that appears to have depth and perspective. 4D ultrasounds work the same way, but they take multiple 3D images over time to produce a video.
Why Doesn't Your Doctor Order 3D and 4D Ultrasounds?
Although these techniques produce more striking images and may seem more advanced, they don't provide a substantial amount of extra diagnostic information. Your doctor can perform most typical screening tests with only the information in a 2D ultrasound, making 3D and 4D techniques unnecessary for the standard viability and full anatomy scans most women receive during pregnancy.
While ultrasounds are safe, a process known as thermal absorption causes tissues in your body to convert some of the mechanical energy in the soundwaves into heat. The additional heat created by 3D or 4D ultrasounds most likely doesn't cause any harm, but many doctors err on the side of caution and stick to 2D ultrasounds for routine procedures.
Are 3D or 4D Ultrasounds Harmful?
It's unlikely that 3D or 4D ultrasounds pose any danger to you or your baby, but you should still follow your doctor's advice and recommendations when imaging your baby. Always discuss your plans with your doctor, especially if you plan to schedule a 3D or 4D nondiagnostic ultrasound beyond the standard two diagnostic ultrasounds.
For more information on ultrasound scans, contact a professional near you.
