Everything You Need to Know About Your 20 Week Ultrasound

Last Updated: February 16, 2024
Liesel Teen, RN-BSN

By Liesel Teen

BSN, RN, Practicing Labor and Delivery Nurse

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Anyone who is pregnant or knows someone who is or has been pregnant has heard of the 20 week ultrasound – which I think is basically everyone.

Midwives, OBs and nurses alike will all also refer to it as the ANATOMY SCAN, because this is your first glance into how your little one is REALLY developing, inside and out!

It sounds like a big deal–and truthfully, it can be a little scary. But it’s also a super exciting pregnancy milestone!

Have no fear, mama! We are going to break the 20 week ultrasound down into itty little bits and make sure that you have all your questions answered.

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What is the 20 Week Ultrasound Appointment?

The 20 week ultrasound is an ultrasound scan performed by an ultrasound technician that is a specialist in pregnancy anatomy scans.

This specialist will take a deep look into things like heart health, organ development, growth in the womb, and screen for some of the more common issues that can be spotted before birth. The results are then shared with your provider for review and discussion.

Knowing that this might be the pregnancy scan where you find out about possible defects, delays or other abnormalities is a little nerve-wracking. But remember, early intervention, education, and knowledge are key to giving baby their best possible outcome.

So even if the 20 week scan gives you unexpected or shocking news, it’s so amazing that you can find out now. Because there’s so much your provider can do!

Related Reading: My Favorite Baby Registry Items (as a Labor & Delivery Nurse!)

Is Having a 20 Week Ultrasound Necessary?

Strictly speaking, the 20 week ultrasound (and all ultrasounds) are actually voluntary. Your doctor might mandate a scan at some point if you are showing signs of complications, but you never HAVE to have a scan – it just might go against medical advice.

Remember this, if you’re wondering if it’s necessary: ultrasound is proven to be very safe when used at the right time and by an appropriately trained and responsible clinician. 

That said, there are still measurable impacts upon the body when ultrasound is used (although they’re very minimal–see far below for more details). The long term effects of these things are unknown, so most research cautions patients to seek ultrasound services from only a trained medical professional, and only for legitimate medical reasons.

That’s right,  mama. If you see that fetal photographer’s billboard on Main Street, just keep rolling by. You’ll get plenty of pictures to take home from your care provider if you ask.

More 20 Week Ultrasound Questions

But what will you see in the ultrasound? What happens during the 20 week anatomy scan? What does the scan look for?

These are the really important questions to keep asking yourself as you prepare. If you know the right things to consider as you work with your provider, the 20-week ultrasound appointment will be ten times more valuable.

What Happens at the 20 Week Ultrasound?

During the scan, you’ll see the typical range of medical technology. If you’ve had other ultrasounds, you’ll know that this will consist of a probe being pressed against the side of your abdomen, typically across multiple locations. This will be necessary as the baby is always in a different place or tends to roll when their quiet calm world is disrupted by the ultrasound.

The sonographer will be focused on capturing key milestone data to help plot your little one’s development on a curve full of averages. This helps them know if the size of your baby’s organs, head, and other bits are growing in time with the data.

He or she will also be looking at specific parts of the body, such as the heart and the lungs, to attempt to spot defects or conditions that might complicate either childbirth or the child’s life.

Luckily, care providers that operate in this space tend to be familiar with the fears that parents-to-be have, and are usually prepared to provide peace of mind or a solid understanding of the implications if something less than ideal is apparent on the ultrasound.

What Specific Defects or Abnormalities are Screened for During the Anatomy Scan?

The anatomy scan you have at 20 weeks (actually, don’t tell anyone, but it’s actually anytime between 18 and 22 weeks) will provide insight to your medical staff on whether or not your baby has any of the most significant conditions visible at this time in littles’ development.

This specialist will look at the heart, brain, face, other organs and spine to ensure these all look like they are developing well. 

Within these areas, there are a few common baddies that the sonographer will be screening for.

Commonly Screened for Conditions and Defects

  • Anencephaly – a condition where significant portions of the baby’s head may not have developed
  • Bilateral renal agenesis – the absence of one or both kidneys
  • Cleft lip – a condition where baby’s lips or mouth have not properly formed together, leaving a “cleft”
  • Diaphragmatic hernia – a defect where your sonographer can spot an abnormal opening in the diaphragm muscles between the chest and abdomen
  • Edwards’ syndrome, or T18 – a chromosomal condition that can cause abnormalities that range across several parts of the body
  • Omphalocele – a weakness of abdominal muscles where the umbilical cord attaches
  • Gastroschisis – a birth defect that affects the abdominal wall, potentially leaving intestines outside the bottom from a hole beside the umbilical
  • Lethal skeletal dysplasia – a form of skeletal dysplasia (sometimes referred to as dwarfism), where the placement or development of bones may result in the infant’s inability to survive
  • Open spina bifida – a condition affecting the spine, where the tube that holds the nerves doesn’t close all the way
  • Patau’s syndrome, or T13 – a chromosomal condition that results in severe intellectual disabilities and physical abnormalities
  • Serious cardiac abnormalities – basically, anything that might impair heart function. This may be an impairment of the valves, defects in the ventricles, abnormal development of the chambers of the heart, or problems with the aorta (to name a few)

Now, these are all obviously big and scary. Remember, though, that most of these happen for very specific reasons and occur very seldom in a union of healthy parents.

As always, your doctor knows how common these things are spotted. Your sonographer will glance for these without batting an eye, and be on to happier things before you even stop to wonder what they saw.

When Will You Get the Results of Your Scan?

If any of the more concerning defects or abnormalities are present, you will find out immediately, either while the sonographer works or after they consult with your regular care provider.

The long and short is that you don’t have to wait to find out something like this. It is in your best interest, as well as your doctor’s, to identify and acknowledge these types of things early. 

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Finding Out the Gender at the 20 Week Ultrasound

The great thing–and yes, you deserve a GREAT great thing after learning about that–is that you will also likely learn the gender of your baby during this scan (assuming your primary physician hasn’t already pointed it out). This is an almost surefire time for that little one to show us what he/she’s got!

A little tip: see if you can spot it for yourself. The best way I’ve found is to look for a hotdog or a hamburger. Kind of a gross metaphor? Maybe. About as silly as it gets? Absolutely.

The fact remains, mama, that this is the easiest metaphor to watch out for. A developing vulva presents as three more-or-less parallel lines running down the baby’s diaper area. Your little man will have a tiny pokey hotdog that projects from the main unit.

Related Reading: Gender Reveal Ideas

Optional 3D Imaging at Your 20 Week Ultrasound

During the 20 week scan, you might be able to ask your sonographer for some 3D images, or at least a look at the kiddo in the 3D scan. 

This isn’t a standard, and it’s definitely not required. You might always want to check in advance to see if it’s covered with your insurance company. Because it’s elective, you might be surprised to find a bill if you don’t take the time to check.

Regardless, if you’re looking for a 3D or 4D keepsake, THIS is the place to get it. Do not risk anything on a commercial ultrasound photography studio, where medical certification and licensing may not be required to operate the ultrasound machine.

20 Week Ultrasound Problems

So we’ve talked a little about what kinds of things might be wrong. But what’s a mama to do if you receive the bad news? What if the ultrasound shows a problem?

Well, you can expect that one of two things will happen:

  • The specialist will explain that they couldn’t complete the exam without some further review, and ask you to reschedule for another appointment as soon as possible
  • They consult with your provider and then share some of the initial findings. Depending on the defect or abnormality, they will then refer you to a specialist

You can guess flat out, mama. This is going to be no fun. 

It’s positively heartbreaking to have a little one who is unwell, even OUTSIDE of the womb. I can only imagine how hard it is when you have a little one struggling INSIDE the womb.

Ultimately, if your little one has any of these problems, you will have a range of treatment options–at least, typically.

Be sure to dig deep with your care provider to ensure that you understand them fully and have all the information necessary to make an informed decision as you move forward.

Chances of Abnormality at 20 Week Scan

Remember, some of these defects and abnormalities are more or less common than others. Your chances are pretty low. According to the CDC, only about 3% of all babies born in the United States are affected by such a defect or condition. 

And that’s an AVERAGE, including some of the more common and less concerning incidents. Edwards syndrome, for example, only occurs in about 0.03% of all US births.

So take a big breath, remember what questions you want to ask, and remember to take joy and pride in the baby-making process. You can’t live your life in all the what-ifs, lady. If you try, it’s going to be a LOOONG pregnancy. Trust you me, oh ye maker of the baby-babes. 

Can the 20 Week Pregnancy Scan Harm Mama or Baby?

While we’re reviewing risk and dangers, I wanted to emphasize a point that I made earlier about how safe ultrasound is. VERY SAFE, according to most clinicians and basically all the scientists ever. Well, maybe not ever–there was probably a time when they thought ultrasound would cook your guts and give you a new appendage in the spot of your choosing.

Kidding, of course. At least, I hope I am.

See, ultrasound uses a different kind of radiation than you typically think of when you think of x-rays or doomsday nuclear fallout. It’s even safer than when you turn on your MICROWAVE.

These things use ionizing radiation, you see. That’s what makes stuff heat up rapidly or what penetrates your body so thoroughly that it can be caught on film, giving us a great shot of dem bones dem bones. Can I get a hallelujah?

What’s the Difference in the Radiation Used in Ultrasound?

Ultrasound, by contrast, uses non-ionizing radiation.

That other kind of radiation, the kind that’s harmful, is ionizing radiation. Ions are like energy superchargers that can excite the water in your body or impact your DNA directly, which is why they are more dangerous.

Because ultrasound doesn’t ionize your cells, it’s a lot less risky. The FDA does mention that ultrasound might warm up the tissue that composes your (or your baby’s) organs or create small pockets of gas that might be disruptive to the tissue or fluids around it.

It’s for this reason that I recommend you forego the fast-food version of ultrasound and ensure you’re putting your body–and that of your little one–in the right hands.

Related Reading: Your Pregnancy Announcement to Family and the Coolest Ways to Do It (in person!)

How to Prepare for Your 20 Week Ultrasound

What preparation you need to do for your 20 week ultrasound appointment is up to your provider. Be sure to ask during the prenatal visit immediately preceding your 20 week anatomy scan

What kinds of things they want you to do can vary. A common requirement is that you drop in with a full bladder. This spaces out your insides so the baby has a nice wide stage. 

Think of it as holding the curtains open by blowing up a giant balloon against the window. Your ultrasound can shoot right through the open space the balloon creates, with little to no interference.

Even that isn’t always necessary. Most skilled sonographers would consider that a “nice to have”, not a “need to have”. There’s always an angle, unless baby is totally uncooperative, in which case the bladder won’t make much of a difference either.

No, mama, the real preparation is more about communication and information. Prepare by knowing who you can bring, and what questions to ask.

Can a Partner, Friend, or Family Member Come to the Scan with Me?

Whether or not you can have a visitor will largely depend on your provider’s rules. Under normal circumstances, you are left to decide this for your self–within reason. 

Typically this will be only a single friend, family member, or partner/spouse. If you’re really lucky, they’ll be all three of these things!

And if you really wanna have mom along too, I expect most providers will be a little flexible in this space–at least in the best of times.

Just be sure to ask well in advance. If you show up with all your immediate family, a few cousins, and an honorary uncle that bought you a beer in Florida and you guys just clicked, you might find your crowd turned away at the door.

That’s right. Not left in the waiting room. Left in the “waiting outside”. There’s just never really any reason to bring so many potential sicknesses into a room full of pregnant ladies, ya know?

Questions to Ask at the 20 Week Ultrasound

There isn’t any one specific question you should or must ask during your anatomy scan. Despite that, it’s good to prepare a few 20-week appointment questions based on your own interests, fears, or family history concerns.

If you need a little guidance, consider the following questions as a baseline for things you might ask:

  • How does my baby’s development look? Is my little one on track in terms of growth?
  • Are there any concerning conditions you weren’t able to rule out?
  • Is my placenta healthy and serving its purpose?
  • Can you show me the baby’s heart a little closer, and talk me through how well it’s working?
  • What kinds of things might have gone unnoticed with how the baby is positioned? Is it worth looking a little longer if we can get the baby to move?
  • How sure are you on the gender, based on what you saw?

This is actually a really great place to start documenting your pregnancy journey, if you’ve been putting it off. There are SOOO many things you’ll want to remember during this time.

Don’t let pregnancy brain do in these lovely memories. Take the time to start a pregnancy journal, lady. You’ll be so glad you took the time to start–trust me. Grab mine FOR FREE!

Is It Necessary to Remain Quiet and Respectful?

Honestly, I always try to be sure to throw in a joke here and there. Always appropriate? Maybe not, but anyone who has a problem with a little poking and prodding is taking things WAAAY too seriously.

You could explain that your mother had a tail when she was born, and you wanted to know if your baby does, too. Or ask if he/she has six fingers on their left hand.

True story, an associate of mine had a family member who worked as an ultrasonographer, and he was asked if the child had an extra appendage. He didn’t see enough to assume there was, guessing they were joking or just over-worried, and announced, “Doesn’t look like it! Nothing to worry about there, as far as I can see…”

Apparently, they were extremely surprised and disappointed. See, everyone in their family had it, dating back generations. And, sure enough, on closer investigation, it was there.

If you’re going to have some fun, just be sure you have the right kind of sonographer for it, and don’t disrupt their time or efforts too much. The last thing you want is for this professional to be arbitrarily distracted and frustrated by small talk if they are the type to get right down to business.

Tips for the 20 week ultrasound during COVID

When it comes to preparing for the 20 week ultrasound, one of my main pieces of advice is to bring a support person to share in the joy and be there in the event of troubling news, too.

That being said, pregnancy in the time of COVID means most (if not all) of your prenatal appts and scans will be done solo so if this is you…

  • Try to FaceTime/Zoom in your partner or another support person if possible. You can do this with your phone, but most practices will be totally fine with you setting up a laptop/tablet at a spot in the room that makes it really easy for your partner to see and be there for the whole event
  • Ask for permission to record the appointment. This way you and your partner can re-watch it together to share the joy AND re-listen to important information that may lead to follow up questions
  • Schedule virtual follow-up visits to the anatomy scan at a time when your partner can be a part of the conversation. I always think more ears and more questions, especially if something more serious came up, is a good idea
  • Wait to find out the gender until later that day So even if you’re not planning to be team green, have the ultrasound technician write the gender down and put it into an envelope. This way you and your partner can find out later in the day when you are together since your partner can’t be at the appointment in person

I know none of this is ideal, but hopefully, these tips can help ease your mind at least a little bit about going to your 20-week scan solo!

The 20 Week Ultrasound Appointment and You

It’s a wild ride, this pregnancy thing. You’re doing the most amazing thing that a woman can do. With her body, at least. 

This 20 week anatomy scan is a huge milestone, marking progress toward the creation of a viable, independent, and free-thinking lifeform. If that’s not amazing enough, you’re also doing it with style, mama.

Be sure you’re making this a memorable and well-documented part of your journey. Take the time to enjoy the process, and milk that sonographer for all they are worth in terms of information. 

It’s hard to remember when you see them every week or two under the clinical conditions, but talking about and looking at babies is not the only thing your OB is doing. In their downtime they are jetting quickly back and forth from delivery ward to clinic and back, catching babies and checking vitals, sewing up little bits and making small talk.

Because of this, it’s important to take full advantage of the sonographer’s time. This is what they do all day, every day. They are experts on ultrasound and infant development. And trust me, babe: they’ve seen it ALL.

So when it’s time for that 20-week ultrasound appointment, take your full self to the clinic and invest all your heart into feeling and seeing and learning. You owe it to yourself, your baby, and that little one’s future!

Happy baby-making, mama!

Related Reading: Everything You Need to Know About Pelvic Pain During Pregnancy (Right Now!)

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Liesel Teen, RN-BSN

Liesel Teen

BSN, RN, Practicing Labor and Delivery Nurse

As a labor and delivery nurse, I’ve spent countless hours with women who felt anxious — even fearful — about giving birth. I want you to know it doesn’t have to be that way for you!

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