What are 2D, 3D, and 4D ultrasounds?
Ultrasound is a way to look inside the body with high-frequency sound waves. It works just like the sonar on boats, which use sound waves to locate things underwater. The ultrasound machines used for medical imaging use waves between 2 to 20 megahertz – that's about 100 times higher than the top of the range we're able to hear (20 to 20,000 hertz). The waves bounce off tissues to create a picture on a screen. That picture is called a sonogram.
- 2D ultrasound is the standard ultrasound that healthcare providers use. This process creates simple, black-and-white images that create a cross-section view, with bright spots for denser materials like bone.
- 3D ultrasound uses the same basic idea as 2D ultrasound, but takes many images from different angles and processes them together to create an image that looks like a real photograph.
- 4D ultrasound adds a fourth dimension – time. In a 4D ultrasound, a series of 3D images is put together to form a low-resolution video.
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What ultrasounds will I have during pregnancy?
You'll probably have a 2D ultrasound about halfway through your pregnancy (between 18 and 22 weeks). During your ultrasound, a technician will use a handheld instrument called a transducer to send sound waves through your uterus. These waves bounce off your baby, and a computer translates the echoing sounds into video images that reveal details of your baby's body, position, and movements. You'll be able to hear the heartbeat and if your baby is awake, you'll see movement on the screen. When you're done, the technician will probably give you a few black-and-white images as a keepsake.
Many women will have an earlier 2D ultrasound as well. If your provider needs to do an ultrasound in the first trimester, she may use a vaginal probe to get closer to your uterus. These early scans are used to date a pregnancy and due date, and check on suspected problems such as ectopic pregnancy.
Find out more about ultrasounds during pregnancy.
Is 3D ultrasound better than 2D?
Not usually. For most pregnancies, 3D ultrasound won't give any more usable information than a standard 2D image. That's why most healthcare providers don't use 3D ultrasound regularly.
There are some exceptions. 3D ultrasound can be useful to diagnose or monitor conditions that are harder to spot on a regular ultrasound. These can include cleft palate or other visible physical problems. If your provider recommends this, your 3D ultrasound will be done along with other ultrasounds in a medical office and covered by insurance.
Can I get a 3D ultrasound at a private clinic near me?
It's not a great idea. The Food and Drug Administration, which regulates medical devices, strongly discourages 3D and 4D ultrasounds for keepsake images and videos.
Part of the reason is that all medical devices should be operated by trained, licensed professionals. In a doctor's office, you can be confident of your care team's skills. If you go to a private clinic offering 3D and 4D ultrasound (like those in malls), you're going to a business that likely operates more like a portrait studio than a medical office.
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There's no guarantee that staff at these clinics are trained properly – or that the ultrasound operator will be qualified to help you if you have questions, or if your ultrasound reveals a problem.
Is 3D and 4D ultrasound safe?
Though there's no proven risk, healthcare providers advise against getting 3D ultrasounds that aren't medically necessary or 4D ultrasounds.
Waves in the megahertz range have enough energy to heat up tissues slightly, and possibly produce tiny bubbles inside the body. Experts don't know enough about the effects to say that unneeded ultrasounds are totally risk-free.
Part of the problem is that 3D ultrasounds and 4D ultrasounds take longer than 2D ultrasounds, so your baby is exposed to a lot more sound waves. Some private clinics encourage moms-to-be to return for multiple sessions, which means even more exposure for their babies.
That said, you may have a personal reason for wanting to have a 3D image or 4D video made.
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If you're interested in 3D ultrasound pictures, start by asking at your provider's office. If they have the equipment, they may be able to provide you with a few pictures during a regular scan, or schedule an additional one at an out-of-pocket cost.
If this isn't an option, look for a reputable private clinic and ask about their technicians' qualifications. Aim for the shortest procedure that will get you what you're looking for, and avoid going in more than once during your pregnancy.
