Level II Ultrasound in Midpregnancy


When Should You Do a Fetal Anatomy Survey

Pregnant woman holding an ultrasound photo
Photo © Blend Images/Getty Images

A detailed anatomy ultrasound is recommended during pregnancy from 18 to 22 weeks. This is typically a transabdominal ultrasound, as opposed to transvaginal scans of earlier ultrasounds during your pregnancy.

The ultrasound technician (or in some cases your doctor) will have you lay down (preferably in a left tilt position) on the exam table. Next, an ultrasonic gel (which is warmed for your comfort) will be placed on your belly.

The technician or your physician will move the ultrasound transducer wand and over your abdomen. You will feel them pressing on your belly, but it will not hurt.

During the ultrasound, fetal anatomy and size are assessed. This means that the size of your baby in comparison to other babies of the same gestational age, as well as the placenta, will be evaluated.

Images produced by the ultrasound will appear on the screen. The images will be measured and recorded, and you may be given some to have as keepsakes.

Some hospitals or clinics will let you record the ultrasound session with a recording device, such as your cell phone camera. However, the rules around this vary from doctor to doctor. It's best to ask before your appointment in case the practice requires you to supply the footage that you record.


Fingers and Toes

23 Weeks 3D Ultrasound
Photo © Lue and Krystal Vang

We often talk about how the first thing we'll do after our baby is born is to count fingers and toes. Today, ultrasound technology enables us to count fingers and toes before a baby is born. However, actually being able to count each finger and toe depends on how cooperative your baby is during the ultrasound exam.


Your Baby's Legs

3D Ultrasound Photos 24 Weeks Pregnant - Ultrasound Photos
Photo © A. Phillips

It is more likely that you will be able to see bigger areas on an ultrasound, like your baby's arms and legs. The ultrasound technician will measure your baby's thigh bone (femur), tibia, and fibula. These measurements help them calculate how well your baby is growing for his or her gestational age.

Sometimes it's possible to see the baby kicking, which you may or may not feel at this point in your pregnancy.


Your Baby's Arms

3D Twin Baby B - 18 Week Ultrasound
Photo © M. Horn

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


Baby's Brain and Stomach

Baby Brain Ultrasound
Baby Brain Ultrasound. Photo (c) K. Harrell

As the ultrasound progresses, the ultrasound technician will check your baby's internal structures, which includes the brain.

At this point in fetal development, the appearance of the brain often has a butterfly look. The ultrasound technician will be examining for the presence and anatomic landmarks of your baby's brain. They will also note any anomalies found, such as choroid plexus cysts.

The ultrasound technician will also look at your baby's stomach, urinary tract, kidneys, and other structures during the ultrasound. If any problems are found, you will need to have further ultrasound exams that are usually conducted by specialists called perinatologists or maternal-fetal experts.


Baby Spine

20 Week Spine Ultrasound
Photo © K. Harrell

Your baby's spine will also be examined during the fetal anatomy survey. This is usually one of the most easily recognizable anatomical elements for parents as they watch the ultrasound.

The technician will confirm that your baby's spine and neural tube are completely formed and without cysts.


Baby Heart

Baby Heart Ultrasound
Baby Heart Ultrasound. Photo © K. Harrell

During the ultrasound, the technician will look through your baby's heart. They will measure the fetal heart rate and look for any structural problems, such as defects in the ventricles and other heart anomalies.

If they suspect a problem with your baby's heart, they will most likely recommend a fetal echocardiogram or fetal ECHO.


Placenta and Umbilical Cord

Placenta Ultrasound
Placenta Ultrasound. Photo © K. Harrell

The technician will also closely examine the placenta. Confirming where the placenta is located helps the technician screen you for a condition called placenta previa.

An ultrasound exam also provides a good view of the umbilical cord. 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).

Babies born with a two-vessel cord sometimes experience growth issues and other potential anatomic anomalies. However, most babies born with a two-vessel cord will have a fetal echocardiogram and be born perfectly healthy.


Sex of the Baby

17 Week Ultrasound Photo - It's a boy! - Ultrasound Photos
Photo © J. Rauch

The part of your pregnancy during which you will have a level 2 ultrasound usually corresponds to when the sex of your baby will be visible.

The accuracy depends on many factors, including the cooperation of your baby. If the technician tells you the sex of your baby, ask how certain they are about their prediction.

While it is possible for the ultrasound to be wrong, there is more data in support of determining sex at this point in your pregnancy compared to ultrasounds used earlier in pregnancy (the first trimester).


3D Ultrasounds

18 week 3D ultrasound
Photo © M. Horn

3D ultrasound (and even 4D ultrasound) is becoming more widely available and popular. Many parents find the images more friendly compared to the stark black and white photos of the 2D pictures produced by a standard ultrasound.

While the photos are fascinating, keep in mind that it can be difficult to obtain good quality 3D photographs. Talk to your practitioner about the benefits of 3D versus 2D for your fetal anomaly screen.

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Article Sources
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