What to Expect During a Pregnancy Anatomy Scan

An ultrasound is recommended during pregnancy between 18 and 22 weeks gestation. The anatomy scan is also called a level 2 ultrasound and is an imaging test that allows a health care provider to carefully check your baby's health and development.

While you may have had earlier ultrasounds during your pregnancy, the 20-week anatomy scan looks in greater detail at the different parts of your baby's body. Generally, a health care provider will examine the baby's whole body, including their organs, umbilical cord, and amniotic fluid levels.

Here is some more information about what might occur during your anatomy scan, what health care providers look at, and what certain findings might mean.

What to Expect During the 20 Week Anatomy Scan

A health care provider's office will schedule your anatomy scan to occur sometime around 20 weeks into your pregnancy. You'll be asked to come to the appointment with a full bladder, which helps the ultrasound tech get a better image of your baby. Typically, you can bring one other person to the ultrasound with you.

The anatomy scan is typically a transabdominal ultrasound, meaning the ultrasound tech will use a wand on your stomach, as opposed to a transvaginal ultrasound in the first trimester. An ultrasound typically follows these steps:

1. To begin the anatomy scan, the ultrasound technician (or in some cases your doctor) will have you lie down on the exam table.
2. Next, an ultrasonic gel will be placed on your belly.
3. The technician will move the ultrasound transducer wand over your abdomen. You will feel them pressing on your belly, but it won't hurt you or your baby. However, if you do feel uncomfortable at any time during the scan, it's important to let the health care provider know.

The entire anomaly scan typically takes between 45 and 75 minutes from start to finish, and you often receive results during the appointment. If an ultrasound tech performs the ultrasound, they cannot tell you specific results, so you may need to wait for a health care provider to review the ultrasound and talk to you afterward.

What Exactly Does a 20 Week Anatomy Scan Show?

Between 18 and 22 weeks into your pregnancy, your baby will be large enough for your health care provider to see details of their organs and limbs from head to toe. If you're having multiples, each fetus will receive their own scan.

During a pregnancy ultrasound, the baby's size and features are assessed. The size of your baby, in comparison to other babies of the same gestational age, as well as the placenta, will be evaluated to ensure your baby is developing properly.

Sometimes, follow-up ultrasounds for growth and reevaluation will be suggested based on the findings of the initial scan. Barring any specific high-risk issues, the following areas are examined to rule out birth defects and other anomalies or red flags:

• Brain (including ventricles, cerebellum, corpus callosum, and other key structures)
• Neck (including nuchal fold thickness)
• Face structures (palate, eyes, nose, lips, and ears)
• Heart and lungs
• Spine and ribs
• Abdominal organs (stomach intestines, spleen, liver, gall bladder) and the abdominal wall
• Limbs and digits
• Genitals (if visible, can determine fetal sex)
• Umbilical cord, including vessels and insertion site
• Placenta structure and location
• Cervical length
• Fetal position and movements
• Amniotic fluid

Typically, the images produced by the ultrasound will appear on a screen where you and the technician can see them. The images will be measured and recorded, and you may be given some printouts or sent a link with the images to have as keepsakes.

Here's a closer look at what the anatomy scan will be checking on your baby.

Fingers and toes

Moments after birth, the first thing many new parents do is count ten tiny fingers and ten tiny toes. However, ultrasound technology enables providers and parents alike to count fingers and toes before a baby is even born.

On the other hand, if your baby is very active, it's possible that you may still have to wait until birth to count all fingers and toes individually.

Legs

Unlike the fingers and toes, you will likely be able to clearly see bigger areas like your baby's arms and legs on an ultrasound despite their movement. During the scan, the ultrasound technician will measure your baby's thigh bone (femur). This measurement helps them calculate how well your baby is growing for their gestational age.

Sometimes it's also possible to see the baby kicking, which you may or may not feel at this point in your pregnancy—another potentially exciting moment to look forward to.

Arms

In addition to looking at your baby's legs, the ultrasound technician will also measure the bones of the arms. Depending on their position, you may see your baby waving their arms or sucking their thumb.

Some technicians may even be able to snap a still photo of your baby's arm waving or their thumb firmly planted in their mouth. This type of photo can become a cherished keepsake and a way to remember the moment.

Brain and stomach

During the scan, the ultrasound technician will check your baby's internal structures, including their brain. At this point in fetal development, the appearance of the brain often looks like a butterfly with wings. The ultrasound technician will check for specific anatomical landmarks in the baby's brain that can indicate healthy development. They will also carefully check for any abnormalities.

In addition to your baby's brain, the ultrasound technician will look at the:

• Stomach
• Urinary tract
• Kidneys
• Skull

While every health care provider is different, you can typically expect to be informed of any unusual findings or abnormalities by the end of your appointment. If any potential issues are found, the health care provider will let you know what the next steps will be, such as more testing or specialty appointments.

Spine

Your baby's spine will also be examined during the fetal anatomy survey. You might even be able to spot your baby's spine yourself on the ultrasound since it is often very clearly visible.

The technician will confirm that your baby's spine and neural tube are completely formed and without cysts. Once again, if abnormalities are present, your health care provider will go over these issues with you—usually before the end of your appointment.

Heart

During the ultrasound, the technician will look through your baby's heart to measure the fetal heart rate and look for any structural problems. Ultrasound technology is very advanced, and if any issues are suspected, the health care provider will inform you of the next steps.

It can be helpful to keep in mind that even if a suspected issue is found in an anatomy scan, it does not automatically mean there is a problem. Sometimes, additional tests reveal that the suspected problem is either easily remedied, will be outgrown, or was just an abnormality that showed up in the initial scan but is not concerning.

Placenta and umbilical cord

During your anatomy scan, the technician will also examine the placenta closely. Confirming where the placenta is located (anterior, posterior, lateral, fundal) helps the technician screen you for a condition called placenta previa.

An ultrasound exam also provides a good view of the umbilical cord to confirm that the cord functions properly. A normal umbilical cord has two arteries and one vein. The technician will check to see if you have a three-vessel or two-vessel cord (single umbilical artery or SUA). SUA is rare, occurring less than 1% of the time.

Babies born with a two-vessel cord sometimes experience growth issues or be born prematurely, so the health care provider may monitor your baby more closely if a two-vessel cord is found. However, most babies born with a two-vessel cord will be born perfectly healthy.

Genitalia

Your pregnancy anatomy scan usually coincides with when the baby's assigned sex can be determined through ultrasound. It is rare for ultrasounds at this stage to get the baby's sex wrong, but it can happen, especially if the baby isn't in a position where a clear view can be seen.

The accuracy of this reveal depends on many factors, especially the position of your baby and whether the ultrasound tech can get a clear image. If your baby is not in an ideal position, the tech may not be able to determine the genitalia.

In addition, about 2% of babies are born intersex, meaning they have variations in chromosomes, genitals, or reproductive organs, making it difficult to assign a binary sex.

How to Prepare for Anatomy Scan

Although the uncertainty of what will happen during your anatomy ultrasound can cause feelings of anxiousness or nervousness, it can help to think of an anatomy scan as an opportunity for reassurance that your baby is developing as they should. It's also the perfect opportunity to get a sneak peek of what your baby looks like prior to birth and preparing for the ultrasound isn't as hard as it may seem.

Truthfully, there isn't much preparation needed for an anatomy scan, but you can best prepare for one by wearing comfortable easy to slip in and out of clothing and keeping your bladder full. You can also provide your health care provider with previous exams to compare and observe the development of your baby.

If unexpected issues are uncovered during the scan, a health care provider will be able to address these problems. Always talk to them about any concerns or questions you have so you feel supported in your pregnancy journey.