The Difference Between 2D, 3D, and 4D Ultrasounds

If you're pregnant, you might be wondering what the difference between a 2D, a 3D, and a 4D ultrasound is. Though most women will have at least one ultrasound done in pregnancy, an ultrasound is not always required for healthy pregnancies. As the newer imaging technologies become more widely available in ultrasound, you might hear various terms thrown around like 2D, 3D, and 4D ultrasounds.

There are differences in the types of ultrasounds done during pregnancy. All ultrasounds use sound waves to create a picture. The traditional ultrasound is a 2D or two-dimensional image to create images of a developing fetus. In recent years, ​3D or three-dimensional images, and now four-dimensional images or 4D, have become popular. However, 3D and 4D ultrasounds are not considered standard prenatal tests and insurance may not cover the cost of these types of ultrasounds unless your doctor deems them medically necessary.

2D ultrasound gives you outlines and flat looking images, but it can be used to see the internal organs of the baby. This is helpful in diagnosing heart defects, issues with the kidneys, and other potential internal issues.

3D images are used to show you three-dimensional external images that may be helpful in diagnosing issues such as a cleft lip. A 4D ultrasound generates an image that is continuously updated, much like a moving image.

Each of these types of ultrasound has advantages and disadvantages. Many families prefer the 3D images because they look more like what they perceive a baby to look like in real life than the flatter 2D images. You should talk to your doctor about the type of ultrasound they use, and why. You can also ask your midwife, but only if they have received their ultrasound education. If your doctor or midwife doesn't offer you a 3D or 4D ultrasound and you'd like one, ask him or her about it.

Ultrasounds can be used to check a number of variables when you're pregnant, including:

• How your baby is developing
• Your baby's age
• Any problems in your uterus, ovaries, cervix, or the placenta
• How many babies you're carrying
• Any problems you and/or your baby may be having
• Your baby's heart rate
• Your baby's growth and position in your uterus
• The level of your amniotic fluid
• Signs of Down syndrome

The Food and Drug Administration (FDA) does not recommend that you get ultrasounds done for fun or bonding purposes, citing the use of ultrasound as a medical technology. This means that you should avoid places that offer ultrasounds that are not recommended by your doctor or midwife to avoid any misdiagnosis. Exposure to ultrasound should be regulated by a medical professional and follow the "As Low As Reasonably Achievable" (ALARA) protocol to limit exposure to heat and radiation. While ultrasound is considered safe, there is not enough evidence to ascertain what prolonged exposure to ultrasound may do to a baby.