What is a fetal ultrasound?

Detailed, high-resolution fetal ultrasound is a safe, noninvasive imaging procedure that uses high frequency sound waves to assess fetal growth and development.

On your initial visit to the Center for Fetal Diagnosis and Treatment at Children's Hospital, we always perform another fetal ultrasound in order to confirm your baby's suspected condition. Our high-resolution equipment and team of sonographers and radiologists who are specifically trained in identifying multiple fetal anomalies often discover additional findings that can help with your baby’s treatment or even change the initial diagnosis.

Who you might meet

• Registered diagnostic medical sonographer (RDMS): a certified health professional that specializes in the use of ultrasound equipment and performs the ultrasound (also known as ultrasound technologist). CHOP’s sonographers have decades of experience performing obstetrical ultrasound. All have earned bachelor’s degrees and are certified by the American Registry for Diagnostic Medical Sonographers.
• Radiologist: a medical doctor that specializes in interpreting imaging procedures (like ultrasound, MR or CT) and diagnosing multiple anomalies. Our board-certified, fellowship trained radiologists use highly specialized equipment to ensure the best images possible are obtained at each stage of pregnancy, allowing for more accurate diagnosis of fetal anomalies and the most appropriate management of care throughout the pregnancy.
• Maternal-fetal medicine specialist (MFM): a physician who is board certified in obstetrics and then completes a fellowship program in maternal-fetal medicine, leading to board certification in maternal-fetal medicine. These physicians have advanced, specialized training in prenatal diagnosis and identifying and caring for high-risk pregnancies.

Ultrasound technology

CHOP is equipped with state-of-the-art ultrasound machines and higher frequency probes than are typically used in most offices. These tools allow us to better visualize your baby’s anatomy. Our sonographers are also trained to use advanced 3-D and 4-D techniques that might be needed to best evaluate certain anomalies.

The high-frequency transducers provide the most detailed resolution possible. This can help differentiate between many different diagnoses. For example:

• The exact level of a spinal defect and the spinal cord can be determined.
• Color and spectral Doppler determine the precise location of the placental cord insertions in a case of twin-to-twin transfusion syndrome.
• High resolution ultrasound combined with color and spectral Doppler to evaluate the abdominal vessels can pinpoint the abdominal contents that have herniated into the chest of a baby that has congenital diaphragmatic hernia.

These are just a few of the many complex cases that have been made clear by our imaging team. The team’s expertise in these techniques frequently leads to additional findings or completely alters the initial diagnosis. 

What to expect

A warm gel is applied to your abdomen to help transmit sound waves to your uterus. You may be asked to move into different positions in order to optimize imaging of your baby’s anatomy. You may be asked to walk and eat or drink to encourage fetal movement. In some cases, it is necessary to empty your bladder for an internal scan of the cervix and presenting fetal parts.

Our ultrasounds tend to take longer than traditional exams because we thoroughly examine your baby. Our sonographers are trained to look at every finger, every toe and every facial feature, including the ears and parts of the eyes and nose, which are typically not examined in a routine anatomical survey. We have developed specific protocols designed for each suspected anomaly and we typically devote up to two hours for each initial scan. This will be the longest and most detailed scan you undergo.

Private examination rooms have overhead monitors so you and your family can watch the ultrasound being performed. After the sonographer has completed the detailed ultrasound, an attending radiologist will also come in to scan your baby. When you move on to your next scan, the radiologist will thoroughly examine all the images, discuss the findings with the maternal-fetal medicine specialist and make recommendations for other types of scans that may be necessary to better understand your baby's condition.