baby bump know-how

The Difference Between An Ultrasound & Sonogram, Explained

It’s oddly confusing. We break it down for you.

by Karen Fratti
Updated: 
Originally Published: 

When you’re expecting a child, a lot of information gets thrown your way. Like, *a lot.* Your brain will be boggled, and that’s before “mommy brain” even fully sets in! And while many, many things will confuse you along the way, one of the most common questions expectant parents ask has to do with the proverbial window into the womb. That’s right; we’re talking about ultrasounds vs. sonograms. What’s the difference? Is there a difference? While people often use the terms interchangeably, an ultrasound and sonogram are two very different (but connected) things.

It’s not technically inaccurate to say that you’re going to get an ultrasound or a sonogram when you make an appointment, but one’s the name of the actual procedure while the latter is the result of the procedure. Still confused? Let’s break it down.

Ultrasound vs. sonogram — what’s the difference, anyway?

An ultrasound is a diagnostic procedure that doctors use to take a picture of your uterus at the beginning and throughout pregnancy to monitor how your fetus is growing and affecting your body. A sonogram is an image that this non-invasive procedure produces. Think of the ultrasound as the camera and the sonogram as a picture. You get an ultrasound first. Then you’re left with the sonogram, or image, that your doctor will “read” to inform you of what’s really going on inside.

What is an ultrasound?

An ultrasound is a simple, non-invasive procedure that most pregnant women receive throughout pregnancy. An ultrasound uses sound waves to produce an image, using either a wand or a probe. High-frequency sound waves bounce off of your tissue and then back onto the probe, after which a computer decodes the sound waves to produce the image that comes up on the monitor screen.

A doctor can detect any issues with your uterus or reproductive organs using an ultrasound and check for any abnormalities with your fetus, including the strength of the fetus’s heartbeat.

Types of Ultrasounds

When you think of an ultrasound, you might first imagine the ones that you see performed on TV or in movies. This is a transabdominal ultrasound, where a technician places gel on your belly and then uses a wand — or a transducer — over your stomach to get the images of your uterus and the fetus.

A transvaginal ultrasound takes place when a technician enters through your vagina to get images of your uterus. The probe is inserted about 1 to 3 inches into the vagina during the procedure. The probe is covered in a sheath and lubricating gel before being placed inside the vagina.

In early pregnancy, this is when they will attempt to detect your baby’s heartbeat. The transvaginal ultrasound produces clearer images of your uterus and your ovaries. It’s all about getting a fuller picture of what’s going on! After the 12-week mark, your doc might also use doppler technology to detect and check on your baby’s heartbeat, but there’s no image (or sonogram) as a result.

You will have multiple ultrasounds throughout your pregnancy to check up on the development of the fetus, any movement from the placenta, and any other issues that might arise before your due date. Therefore, getting an ultrasound is one of the best things about your prenatal appointments. It’s the only way to give your fetus a checkup, so to speak.

Before an ultrasound, there's not much to do to prepare for the exam except wear loose-fitting clothing or a two-piece outfit, so you won't have to remove all your clothes. Also, try to empty your bladder about an hour and a half before the exam.

More Types of Ultrasounds

Elastography uses low-frequency vibrations. During an MRI or ultrasound, it assesses the stiffness of your organs. It is an excellent tool to distinguish healthy tissues from tumors or detect liver diseases.

Therapeutic ultrasounds are typically used by occupational therapists to help reduce pain through deep heating. This heals tissue and other internal chronic pain. Therapeutic ultrasounds are also used to capture images of tissue and organs to help determine a diagnosis.

How do you read a sonogram?

Emmanuel Faure/Getty Images

As stated before, the sonogram is the image that will appear on the monitor during your ultrasound. Because it can be grainy, reading a sonogram is best left to professionals. After all, how many moms have peered at a sonogram… only to find what appears to be an alien squirrel?

Fortunately, there are tips to figure out what you’re really looking at when you proudly show the printout to all of your friends and family. The key takeaways? The gray colors are soft tissue, whereas the black areas are where amniotic fluid is. While ultrasound technology advances every day — the doctor might offer a 3D version, for example — picking out the details of the image might still prove tricky. So, try looking for the limbs or the head to orient yourself.

You will also be able to see the biological sex of your fetus with an ultrasound. To see that when you look at the sonogram, check for three little white lines that represent the clitoris and labia on a female. Later in pregnancy, check for a developing penis to indicate a male.

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