18-22 Week Ultrasound Results

If you had an 18-22 week (detailed anatomy) ultrasound, you might be wondering what your results mean. Although this the ultrasound can tell you the likely sex of the baby, it can also give you information about how the baby is growing and developing.

"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 differences in how the organs or structures of the baby are developing. These differences are sometimes called birth defects.
there are no other signs that increase the chance for the baby to have a chromosome difference.

It is important to know that ultrasounds in pregnancy cannot detect all conditions. This is because 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

If the ultrasound does detect differences in how the organs or structures of the baby are developing, more tests might be offered to you. Your health-care practitioner might refer you to a genetics specialist to discuss your result, provide support and arrange more testing, if wanted.

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| Soft markers

The 18-22 week ultrasound can sometimes detect soft markers. Soft markers are not birth defects, and do not usually in themselves cause health problems. Soft markers only raise the possibility that the baby might have a chromosome difference, such as trisomy 21, or another medical condition. It is important to remember that most babies with soft markers are born healthy.

Examples of soft markers:

Hypoplastic (or absent) nasal bone

A 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, but most often it is a normal variation in the baby's development. Your health-care practitioner might offer you a referral to a genetics/MFM centre in your area to discuss your results, and options for more testing.

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 baby's health. An increased nuchal fold could be a sign for trisomy 21, but most often it is a normal variation in the baby's development. Your health-care practitioner might offer you a referral to a genetics/MFM centre to discuss your results, and options for more testing.

Pyelactasis (or pelviectasis)

When pyelectasis is seen on ultrasound, it means there is a mild enlargement of the central area (or "pelvis") of the kidney. This often disappears before birth, and does not result in any problems for the baby. Other times, pyelectasis can be a sign that the urine does not flow freely from the baby's kidney to the bladder. Your health-care practitioner might offer you a referral to a genetics/MFM centre in your area to discuss your results, and options for more testing, including more ultrasounds to monitor the kidneys.

Hyperechogenic 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 practitioner might offer you a referral to a genetics/MFM centre in your area to discuss your results, and options for more testing.

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. EIFs are generally a typical part of the baby's development, but can be a sign for trisomy 21.

Sometimes an EIF is seen on its own without any other findings on ultrasound. If that is the case and your screening test (e.g. enhanced First Trimester Screening or Non-Invasive Prenatal Testing) showed a low chance for trisomy 21, then no further testing is needed.

Other times, an EIF is seen along with other soft markers or other findings on ultrasound. In this case, your health-care provider might offer you a referral to a genetics centre 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, but may also raise the possibility of other conditions. Your health-care practitioner 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 practitioner might offer you a referral to a genetics/MFM centre in your area to discuss your results, and options for more testing.

Choroid plexus cysts (CPCs)

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.

CPCs are generally a normal part of the baby's development, but can be a sign for trisomy 18 if it is seen with physical differences or problems with how the baby is growing. If CPCs are seen on their own and your screening test (e.g. enhanced First Trimester Screening or Non-Invasive Prenatal Testing) showed a low chance for trisomy 18 then no further testing is needed.