18-22 Week Ultrasound Results

If you had a 18-22 week (detailed anatomy) ultrasound, you might be wondering what your results mean. This ultrasound can tell you about the growth and development of the baby.

"Normal" ultrasound

You might be told that your ultrasound was "normal". This means that:

The baby is the right size for its age
The placenta has a normal size and is in the right location
There is enough amniotic fluid surrounding the baby
There are no birth defects that could be seen
There are no other signs that increase the chance for the baby to have a chromosome difference.

It is important to know that ultrasounds have important limitations. Ultrasounds during pregnancy cannot detect all conditions. Some genetic conditions do not result in any birth defects at all, but cause health and learning problems as the child grows. Birth defects are also sometimes missed during the pregnancy, and are only seen after the baby is born. For example, it is difficult to detect some heart defects during the pregnancy.

Ultrasound findings

Sometimes, the ultrasound detects certain differences in how the organs or structures of the baby are developing. This means that more tests might be offered to you to look into this further. Your health-care provider might refer you to a genetics specialist to discuss your result, provide support, and arrange more testing if needed.

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| Soft markers

The 18-22 week ultrasound sometimes detects soft markers. Soft markers can be signs for chromosome differences or other conditions. If you had prenatal genetic screening in this pregnancy, the presence of a soft marker might increase the chance for trisomy 21 or trisomy 18 that was reported by this test.

It is important to remember that soft markers are not "birth defects" and most babies with soft markers do not have a chromosome difference or other health problems.

Examples of soft markers:

Echogenic Intracardiac Focus/Foci (EIF)

An echogenic intracardiac focus (EIF) is a small bright spot in a region of the baby’s heart. EIFs happen due to a small deposit of calcium and are usually seen in a part of the heart that is called a ventricle (which pumps blood to the rest of the body). EIFs are not considered a heart defect and do not cause any problems with the way the heart functions.

Sometimes EIF is seen along with other markers on ultrasound. In this case, your health-care provider might offer you a referral to a genetics centre in your area to discuss your results, and options for more testing.

Other times, EIF is seen on its own without any other markers on ultrasound. In this case, more testing is not recommended.

Increased nuchal fold

An increased nuchal fold (6 mm or more) means that the skin at the base of the neck appears thicker than average. Having an increased nuchal fold does not in itself cause problems with the babies health. An increased nuchal fold could be a sign for trisomy 21. Your health-care provider might offer you a referral to a genetics centre in your area to discuss your results, and options for more testing.

Ventriculomegaly

Inside the brain, there are structures called ventricles that are normally filled with fluid. If the ventricles too large (10 mm or more), you will be told that the baby has "ventriculomegaly". This can be a sign for chromosome differences, certain infections, and other conditions. Your health-care provider should offer you a referral to a genetics centre in your area to discuss your results, and options for more testing.

Hypoplastic nasal bone

Hypoplastic nasal bone is when the nasal bone of the baby is smaller than average. A hypoplastic nasal bone could be a sign for trisomy 21. Your health-care provider might offer you a referral to a genetics centre in your area to discuss your results, and options for more testing.

Short long bones

The ultrasound measures certain arm and leg bones. Sometimes the long bones (humerus or femur) are shorter than average. Short long bones could be a sign of trisomy 21 if seen along with other markers on ultrasound. Your health-care provider might offer you a referral to a genetics centre in your area to discuss your results, and options for more testing.

Echogenic bowel

An echogenic bowel is when the baby's bowel (intestines) look bright on ultrasound. An echogenic bowel can be a sign for a chromosome difference, certain infections, a blockage in the bowel or cystic fibrosis (a genetic condition that affects the lungs and other organs). All the different possibilities can be overwhelming, but it is important to remember the baby will most likely be born healthy. Your health-care provider might offer you a referral to a genetics centre in your area to discuss your results, and options for more testing.

Choroid plexus cysts (CPCs) - no longer considered a soft marker

A “choroid plexus cyst” is a small space (“cyst) that fills with fluid in a part of the brain called the choroid plexus. The choroid plexus makes the fluid that surrounds the brain and spinal cord. These cysts do not cause any problems with the baby’s health or the way the brain functions. Most CPCs disappear by the third trimester of pregnancy.

In the past, seeing a CPC was thought to be a sign for trisomy 18. We now know that CPCs do not increase the chance for any chromosome differences, including trisomy 18. CPCs are a normal part of the baby’s development. Further testing, such as more ultrasounds, is not recommended.