By Sarina Gomez
This article is general information, not medical advice. Ask your midwife, OB-GYN or sonographer about your own pregnancy and scans.
There’s no real difference between a sonogram and an ultrasound in pregnancy: ultrasound is the test that uses sound waves, and a sonogram is the picture it produces. People use the two words interchangeably, so if your doctor orders an ultrasound and your printout says sonogram, it’s the same exam. The rest of this guide explains the other words you’ll hear around a scan, from “sonographer” to “anatomy scan”, so the paperwork makes sense.
Sonogram vs ultrasound in one table
| Word | What it means | Example |
|---|---|---|
| Ultrasound | The technology and the test: sound waves sent into the body, echoes turned into images | “You’re booked for an ultrasound at 20 weeks.” |
| Sonogram | The image the ultrasound produces | “Can I have a copy of the sonogram?” |
| Sonography | Another name for ultrasound imaging as a procedure or field | “Diagnostic medical sonography” |
| Sonographer | The trained professional who performs the scan | “The sonographer will take measurements first.” |
| Scan | Everyday word for the exam, used especially in the UK | “The 12-week scan” |
Cleveland Clinic puts it simply: ultrasound uses high-frequency sound waves to create pictures, and “an ultrasound picture is called a sonogram.” RadiologyInfo adds that ultrasound imaging is also called sonography. In pregnancy, Cleveland Clinic uses “prenatal ultrasound (or sonogram)” for the same prenatal test.
How the picture is made
The word “sonogram” makes more sense once you know what’s happening. As ACOG explains, a transducer sends sound waves into your body. The waves bounce off tissue, fluid and bone, the transducer picks up the echoes, and a computer turns them into images on a screen.
That’s why sonograms look the way they do:
- Fluid looks black, because it returns few echoes. Amniotic fluid is the dark space around your baby.
- Bone looks bright white, because it reflects strongly. Skull and spine stand out first.
- Soft tissue is in between, in shades of gray.
Ultrasound doesn’t use radiation, which RadiologyInfo notes as one of its main benefits.
Terms for the type of exam
Your appointment letter or printout may name the exam in different ways. Here’s what each means:
- Transabdominal ultrasound: the probe moves over your belly with gel. You may be asked to come with a full bladder (ACOG).
- Transvaginal ultrasound: a wand-shaped probe is placed in the vagina, often used early in pregnancy. Cleveland Clinic notes abdominal scans are used after about 12 weeks.
- 2D, 3D and 4D: 2D is a flat, gray cross-section; 3D adds depth so you see the surface of the face; 4D is 3D in motion (Cleveland Clinic). Our 3D ultrasound guide explains how the 3D picture is built.
- Doppler: checks blood flow through vessels, often later in pregnancy.
- Standard, limited and specialized exams: ACOG’s three types. A standard exam checks development and estimates age; a limited one answers one question, such as the baby’s position; a specialized one looks closer when a problem is suspected.
Terms for scans by timing
| Name you’ll hear | When | What it’s for |
|---|---|---|
| Early or dating scan | First trimester; the NHS offers it at about 10 to 14 weeks | Confirms how far along you are and sets the due date |
| Nuchal translucency (NT) scan | Usually 10 to 13 weeks, as part of first-trimester screening | Measures the fluid at the back of the baby’s neck as part of a screening test |
| Anatomy scan, anomaly scan, 20-week scan | About 18 to 22 weeks | Checks the baby’s development and screens for major conditions |
| Growth scan | Later, when needed | Tracks size if there’s a reason to |
Sources: NHS 12-week scan, ACOG prenatal screening, ACOG ultrasound exams and the NHS 20-week scan.
For what each stage actually looks like, see our guide to ultrasound pictures by week, and for the labels and numbers printed around the image, read how to read an ultrasound picture.
Your sonogram as a keepsake
Most parents leave with a printed sonogram, and it’s often the first picture of their baby they share. Thermal printouts fade, so photograph or scan yours soon. If you’d like to imagine the face behind it, SeeMyBaby turns one photo of your sonogram, 2D, 3D or 4D, into an imagined newborn portrait in about a minute. It’s for fun: the app doesn’t read anything medical from the image, and a clear 3D profile gives a closer result than a grainy 2D one.
Sources
- Cleveland Clinic: Ultrasound and Pregnancy Ultrasound
- RadiologyInfo (ACR/RSNA): Obstetric Ultrasound
- American College of Obstetricians and Gynecologists: Ultrasound Exams and Prenatal Genetic Screening Tests
- NHS: 12-week scan and 20-week screening scan
More plain-English scan guides are on the SeeMyBaby blog.
Questions parents ask
Is a sonogram the same as an ultrasound?
Yes, for practical purposes. Ultrasound is the test, and the sonogram is the image it creates.
Why do some doctors say sonogram and others say ultrasound?
It’s habit and region. Both words are correct; “scan” is also common, especially in the UK.
Is a sonogram safe during pregnancy?
ACOG says there’s no evidence ultrasound harms a developing baby, and recommends that scans be done for medical reasons by qualified professionals. Ultrasound uses no radiation.
Who reads my sonogram?
A sonographer usually performs the scan, and a radiologist or your obstetric provider reviews the images and shares the results with you.
