By Sarina Gomez
This article is general information, not medical advice. Ask your midwife, OB-GYN or sonographer about your own pregnancy and scans.
The 20 week ultrasound, often called the anatomy scan, is the detailed check of your baby’s body in the middle of pregnancy. It’s usually done between 18 and 22 weeks and looks at the brain, spine, heart, face, kidneys, belly and limbs, as well as growth, the placenta and the fluid. The pictures you take home are mostly black-and-white 2D images: a clear side profile, a hand or a foot, sometimes a view that shows the sex.
When the anatomy scan happens
The anatomy scan takes place in the middle of the second trimester. ACOG says you should have at least one standard ultrasound exam during pregnancy, usually at 18 to 22 weeks. In England, the NHS offers it between 18 and 21 weeks, and sometimes up to 23 weeks.
| US (ACOG) | UK (NHS) | |
|---|---|---|
| Name | Standard ultrasound exam, anatomy scan | 20-week screening scan, mid-pregnancy scan |
| Timing | usually 18 to 22 weeks | usually 18 to 21 weeks, up to 23 |
| Length | varies by clinic | about 30 minutes, can be longer |
What the 20 week scan checks
The anatomy scan checks how the baby is growing and looks for major physical differences. According to ACOG, a standard exam checks physical development, screens for major congenital anomalies and estimates gestational age. It can also show the baby’s position, movement, breathing and heart rate, an estimate of size and weight, the amount of fluid, where the placenta is, and how many babies there are. ACOG’s screening guide adds that the scan between 18 and 22 weeks looks at the brain and spine, facial features, abdomen, heart and limbs.
The NHS lists what the sonographer looks at: the bones, heart, brain, spinal cord, face, kidneys and tummy. It also names 11 specific conditions the scan screens for, from open spina bifida and cleft lip to serious heart conditions. If anything needs a closer look, you’ll be told what happens next, which is often a follow-up scan.
This article doesn’t interpret results. If something on your scan worries you, your midwife, OB or the sonographer’s report is the place to start.
What 20 week ultrasound pictures can show
At 20 weeks your baby’s features are recognizable on ultrasound for the first time. ACOG’s week-by-week guide says ears, nose and lips become recognizable on an ultrasound exam around 17 to 20 weeks.
The pictures parents usually take home:
- The side profile. Forehead, nose, lips and chin, clearly outlined. This is the classic 20 week picture.
- A hand or foot. Often with fingers or toes you can count.
- The spine, like a string of white beads.
- A front-on face view, which can look skeletal. That’s normal: ACOG notes fat only starts forming under the skin at 21 to 24 weeks, so the face is still thin, and bone shows up bright white on ultrasound.
- A view showing the sex, if you’ve asked and the baby is lying well.
Most anatomy scans are 2D. Some clinics may show a 3D view, but the medical exam uses 2D. For how pictures change from scan to scan, see ultrasound pictures by week.
Can you find out the sex at the 20 week scan?
Often, yes, if you want to and if the baby cooperates. ACOG says that during a standard exam, “if the fetus is in a good position, it may be possible to tell the sex.” The NHS says you may be asked whether you’d like to know.
If you’d rather keep it a surprise, tell the sonographer at the start so they don’t say it or point it out on the screen. You can also ask them to write the result on a card and seal it for a reveal. Our guide on when you can find out the gender compares this with blood tests and other options.
How to prepare and what to ask
There’s little to prepare, but a few steps make the day easier:
- Ask the clinic about your bladder. Instructions vary; some want it partly full.
- Wear a two-piece outfit so you only lift your top.
- Plan for about 30 minutes, and longer if the baby isn’t lying well.
- Ask about pictures before you go. The NHS suggests checking with the hospital or clinic beforehand if you’ll need to pay for pictures.
- Decide in advance whether you want to know the sex, and tell the sonographer.
Good questions for the sonographer:
- “Can you show me the profile so I can take that picture home?”
- “Is everything you needed to see visible today, or do I need to come back?”
- “Who will explain the report to me, and when?”
If the baby won’t cooperate
A baby lying in an awkward position is common and usually just means more time. The NHS says you may be asked to walk around or eat something and come back after a short break. If clear images still aren’t possible, you’ll be offered another appointment before 23 weeks.
This is about getting the views the sonographer needs, not about pictures. A blocked face on the day doesn’t mean anything is wrong.
What the anatomy scan can’t tell you
No ultrasound finds everything. The NHS states that “the scan cannot find all conditions,” and RadiologyInfo says obstetric ultrasound “cannot identify all fetal abnormalities.” A clear scan is reassuring, but tell your midwife or doctor about any symptoms or worries at any stage.
It also can’t tell you what your baby will look like. The face is still thin, there’s no color, and features change as fat builds up in later weeks. Our article on 3D ultrasound vs the real baby explains why scans and newborns look different.
Imagining a face from your 20 week picture
If you’d like to imagine the face anyway, SeeMyBaby turns one photo of your scan into an imagined newborn portrait in about a minute. A 20 week 2D profile works, but the result is more imagined than one from a clear 3D scan with a visible profile. It’s for fun, not a prediction and not a medical view of your scan. The blog has more scan guides, from the 12 week scan onward.
Sources
- ACOG: Ultrasound Exams
- ACOG: Prenatal Genetic Screening Tests
- ACOG: How Your Fetus Grows During Pregnancy
- NHS: 20-week screening scan
- RadiologyInfo (ACR/RSNA): Obstetric Ultrasound
Questions parents ask
Can you see the baby’s face at the 20 week scan?
Usually you’ll see the profile clearly. ACOG notes ears, nose and lips become recognizable on ultrasound around 17 to 20 weeks, though the face still looks thin.
How long does the 20 week ultrasound take?
The NHS says about 30 minutes, and it can take longer if the baby isn’t in a good position.
How accurate is the gender at the 20 week ultrasound?
It depends on the baby’s position and the view the sonographer gets. ACOG says the sex may be visible “if the fetus is in a good position,” so ask how confident they are.
Why does my 20 week ultrasound look like a skeleton?
Bone shows up bright white on ultrasound, and the baby has very little fat yet. ACOG notes fat only begins forming under the skin at 21 to 24 weeks.
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