Everything You Need to Know About Your 20-Week Ultrasound

Last Updated: March 14, 2024
Liesel Teen, RN-BSN

By Liesel Teen

BSN, RN, Practicing Labor and Delivery Nurse

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Anyone who is pregnant, has been pregnant, or knows someone that is/has been pregnant has heard of the 20-week ultrasound – this is basically everyone, right?

You might hear your OB provider refer to it as the anatomy scan. This is your big, first glance into how your little one is developing, inside and out!

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

Have no fear, mama! We are going to break the 20-week ultrasound down to make sure you know exactly what to expect!

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What is the 20-week ultrasound appointment?

The 20-week ultrasound is an ultrasound scan performed by an ultrasound technician. Often, it takes place in your regular OB office, but you might have to go to a different location.

The technician will dive into things like heart health, organ development, and baby’s growth. They’ll also 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 ultrasound 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 your baby the best possible outcome.

Related Reading: 20 Pregnancy Milestones You Don’t Want to Miss

Is having a 20-week ultrasound necessary?

Technically speaking, the 20-week ultrasound (and all ultrasounds, for that matter) is voluntary. Your doctor might strongly recommend a scan at some point, especially if you’re experiencing any complications, but you’re never obligated to undergo a scan.

Consider this if you’re questioning its necessity: ultrasound has been proven to be very safe when used at the right time and by a properly trained and responsible clinician.

However, there are still measurable impacts on the body when ultrasound is used (though they’re very minimal). The long-term effects of these impacts are unknown, so most research advises patients to seek ultrasound services only from a trained medical professional and only for legitimate medical reasons.

In other words – skip the private, pay-out-of-pocket fetal photographers.

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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 and ask about, you will get so much valuable information and insight out of this appointment.

What happens at the 20-week ultrasound?

The ultrasound technician will use some gel and a probe on the outside of your belly. He or she will take their time moving through different parts of your baby, examining all organs and parts very closely.

They will focus on capturing key data to track baby’s development on a curve full of averages. This helps them know if the size of your baby’s organs, head, and other areas are growing in time with the data.

The technician will look at specific parts of the body, such as the heart and the lungs, and look for markers of spot potential defects or conditions.

Luckily, care providers that operate in this space tend to be familiar with the fears that parents-to-be have. They 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 around 20-weeks (can happen anytime between 18 and 22 weeks) will provide insight to your medical staff on whether or not your baby has any significant conditions visible at this time in their development.

This specialist will look at the heart, brain, face, other organs, and spine to ensure these are developing as expected.

The conditions discussed below are pretty rare so don’t spend too much time stressing over them. I just wanted you to be aware of some of the things they will be looking 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 Trisomy 18: 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
  • Platyspondylic 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 Trisomy 13: 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 big and scary words. Remember, though, most of these are very rare!

More common, lower risk ultrasound findings

  • Placenta previa: occurs when the placenta is partially or completely covering the cervical opening. Depending on when it’s identified, the placenta may or may not move throughout pregnancy. Your safest mode of delivery will depend on how far the placenta is from the cervix close to delivery time
  • Breech positioning: if your baby is breech during this ultrasound I wouldn’t even bat an eye. Babies change their positions a fair amount while growing in your belly so I would advise you not to be overly concerned with baby’s position until much closer to your due date
  • Single umbilical artery: typically an umbilical cord has two arteries and one vein. For a lot of women, having a two-vessel cord (aka single umbilical artery) doesn’t impact their prenatal care. Some babies with a two-vessel cord might be at an increased risk for improper growth and development in utero
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When will you get the results of your scan?

If any of the more concerning defects or abnormalities are present, you should find out immediately. Either while the ultrasound technician works or after they consult with your OB provider.

The long and short is that you shouldn’t have to wait a while for your results. It is in your best interest, as well as your baby’s and provider’s, to identify and acknowledge these types of things early so i

Finding out baby’s sex at the 20-week ultrasound

The great thing is that you will also likely learn the sex of your baby during this scan (assuming you and your partner plan on finding out).

Related Reading: 40+ Beautiful and Unique Gender Reveal Ideas You’ll Love

20-week ultrasound problems

So, we’ve touched on the types of issues that might arise. But what’s a mama to do if you receive less than ideal news?

What if the ultrasound reveals a complication?

In such a scenario, you can anticipate one of two outcomes:

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

Receiving news about potential complications with your little one can be heartbreaking and downright scary.

In the end, if your baby is diagnosed with any of the discussed complications, it’s essential to be referred to a high-risk OB specialist team. This team will collaborate with your OB provider to oversee your pregnancy.

Make sure to thoroughly discuss these matters with your provider to ensure you have a complete understanding and all the essential information to make informed decisions as you progress.

How common is bad news at 20-week scan?

We’ve discussed the purpose of the anatomy scan and briefly touched on its specifics. Now, let’s step back for a moment and delve into what birth defects entail more generally.

According to The March of Dimes, “Birth defects are structural changes at birth that can affect almost any part of the body. They may impact how the body looks, functions, or both.” Even though birth defects can technically occur at any time during pregnancy, most occur during the first trimester when the baby’s organs are forming.

The level of intervention and treatment required will vary depending on the type of birth defect detected.

Keep in mind that the majority of conditions screened for during the 20-week ultrasound are rare. According to the CDC, approximately 3% of all babies born in the United States are affected by such defects or conditions. This 3% is an average and includes some of the more common and less concerning incidents. For example, Edwards syndrome only occurs in about 0.03% of all US births.

So, take a deep breath, remember the questions you want to ask, and don’t forget to take pride and joy in what your body is accomplishing, mama! In case no one has told you yet, you’re doing a darn good job.

Can the 20-week ultrasound harm mama or baby?

While we’re reviewing risk and dangers, I want to emphasize a point I touched on earlier about the safety of ultrasounds. According to the governing body of obstetricians, ACOG, “No links have been found between ultrasound and birth defects, childhood cancer, or developmental problems later in life.” (source)

ACOG does recommend that ultrasounds be performed only for medical reasons and only by medical professionals because there’s a possibility that effects might be identified down the road.

Long story short, the occasional, medically necessary ultrasound should not jeopardize the safety of you or your baby.

Related Reading: The Very Best Ways to Do a Pregnancy Announcement to Family

How to prepare for your 20 week ultrasound

  • Schedule the appointment: Ensure you have a scheduled appointment for your 20-week ultrasound
  • Confirm instructions: Check with your healthcare provider for any specific instructions or preparations they recommend
  • Hydration: Follow any instructions regarding hydration, such as drinking water to ensure a full bladder if requested by your provider
  • Comfortable clothing: Wear comfortable clothing that allows easy access to your abdomen for the ultrasound
  • Bring support: Consider bringing a support person with you for emotional support and assistance
  • Prepare questions: Make a list of questions or concerns you may have for your healthcare provider during the ultrasound appointment
  • Familiarize with the procedure: If you’re unfamiliar with ultrasounds, take some time to learn about the procedure and what to expect
  • Relaxation techniques: Practice relaxation techniques to help stay calm and comfortable during the ultrasound
  • Arrive on time: Arrive at the appointment on time to ensure you have sufficient time for the procedure and any additional discussions with your healthcare provider

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:

  • Can you show me the baby’s anatomy and explain what we’re looking at?
  • How is the baby’s growth and development progressing?
  • Are there any abnormalities or concerns detected during the ultrasound?
  • Can you determine the baby’s gender, if we want to know?
  • What is the position of the placenta, and is there any concern regarding placenta previa?
  • Are there any signs of conditions such as cleft lip, spina bifida, or heart defects?
  • Can you assess the amniotic fluid levels and the umbilical cord’s position and function?
  • Are there any indications of multiples (twins, triplets, etc.)?
  • Can you estimate the baby’s weight and measurements?
  • Is there any reason for concern regarding the baby’s movements or activity levels?
  • Can you provide images or recordings of the ultrasound for us to keep?
  • Are there any recommendations or follow-up tests based on the findings of this ultrasound?
  • Can you discuss the results of the ultrasound with my partner or support person as well?
  • What should I expect in terms of further prenatal care or monitoring after this ultrasound?
  • Are there any lifestyle or dietary recommendations based on the ultrasound findings?

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.

The 20-week ultrasound appointment and you

This 20-week anatomy scan is a huge milestone, marking progress toward the creation of your sweet little one. If that’s not amazing enough, you’re also doing it with style, mama.

It’s important to take full advantage of the ultrasound technician’s time. This is what they do all day, every day. They are experts on ultrasound and infant development. And trust me, they have 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, seeing, and learning.

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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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