Fetal Imaging

If routine testing during pregnancy detects a possible abnormality, fetal imaging specialists in the Fetal-Maternal Center at Children’s Hospital Los Angeles offer expert diagnosis and treatment. We use advanced imaging tools to get the information needed to create a personalized treatment plan for you and your baby.

Our specialists have rare levels of expertise in fetal imaging options. We offer fetal magnetic resonance imaging (MRI), which many centers don’t have the expertise to perform. Our specialists were also among the first to use MRI to measure brain temperature. These advanced tools allow our doctors to offer more specialized treatments that lead to improved outcomes.

Fetal tests and imaging techniques we offer include:


When you are pregnant, a liquid called amniotic fluid surrounds and protects your baby in the uterus. In amniocentesis, we take a small sample of this fluid for analysis. Amniocentesis allows us to diagnose conditions like spina bifida, cystic fibrosis or genetic disorders before a baby is born.

What to expect during amniocentesis

During amniocentesis:

  1. Your doctor uses an ultrasound, an imaging test that uses sound waves, to see the fetus and amniotic fluid.
  2. We clean and sterilize your belly, then insert a thin needle into the amniotic fluid.
  3. The doctor takes about four teaspoons of this fluid.
  4. The entire procedure takes only about 30 seconds. You may feel some slight cramping or discomfort. Most women resume usual activities the next day.
  5. After the procedure, your doctor sends the amniotic fluid sample to our in-house genetic testing lab for analysis. Your doctor and a genetic counselor review the results with you in a few days.  

Chorionic Villus Sampling

Chorionic villus sampling is a test that analyzes tissue from the placenta, which provides blood and nutrients to developing fetuses. The chorionic villi are tiny structures in the placental tissue that contain genetic information. Analyzing this information lets us detect genetic conditions such as Down syndrome.

What to expect during chorionic villus sampling

We typically perform this test around weeks 10-11 of pregnancy. During chorionic villus sampling:

  1. The doctor uses an ultrasound image to identify the position of your placenta.
  2. While you lie on your back, the doctor inserts a thin, hollow tube (catheter) through the vagina and into the cervix. You may feel a small amount of discomfort or pressure.
  3. The catheter uses gentle suction to remove a small sample of placental tissue.
  4. The entire procedure takes only a few minutes. You may experience light spotting or bleeding immediately after the test. Most women resume usual activities the same day.
  5. Your doctor sends the placental tissue sample to our in-house genetic testing lab for analysis. Typically, a genetic counselor and your doctor review the results with you within a few days.

Fetal Echocardiogram

If a routine ultrasound detects any potential heart problems, we may order a fetal echocardiogram. An echocardiogram is a test that uses sound waves to look at the structures of your baby’s heart. A fetal echo can detect arrhythmias, congenital heart defects and other abnormalities. Echocardiograms present no known risk to either mother or baby.

What to expect during a fetal echocardiogram

During a fetal echocardiogram:

  1. A trained technician applies a special gel to your abdomen. This technician uses an ultrasound probe (a tool that looks like a small wand) to take pictures of the fetus. 
  2. A fetal echocardiogram can take anywhere from 30 minutes to two hours, depending on the complexity of your baby’s heart.
  3. An expert from fetal cardiology analyzes the results of the echocardiogram. You may have to wait a week or two for your results, depending on the complexity and how far along you are in your pregnancy.

Fetal Magnetic Resonance Imaging (MRI)

Magnetic resonance imaging (MRI) uses radio waves, magnets and a computer to create two-dimensional or three-dimensional images. We can use MRIs to take pictures of your baby without using radiation. Your doctor might order a fetal MRI if you or a family member has genetic risks that could affect your baby.

What to expect during fetal MRI

During a fetal MRI:

  1. You lie on the MRI table. This table slides into the MRI machine, which looks like a long rectangle with a hole in the middle. The MRI machine is open on both ends, like a tunnel.
  2. While inside the MRI machine, you must remain still while a technologist takes pictures. The machine makes a whirring or thumping sound. If you like, you may wear earplugs or listen to music for distraction.
  3. The test takes around 30-45 minutes. Usually, your doctor discusses your test results with you within a day or two.


Ultrasounds use sound waves to view inside your body and look at your baby. Ultrasounds are a routine part of your prenatal care. If needed, we use advanced imaging techniques to examine the fetus in further detail. These tests include:

3D ultrasound

3D ultrasounds create 3D images of your baby’s body, organs and blood flow. During a 3D ultrasound:

  1. You recline on an exam table with your abdomen exposed. A technologist applies gel to your abdomen. This gel helps transmit sound waves so we can get an accurate image.
  2. The technologist touches a wand-like tool to your abdomen. This tool sends an image to a computer screen. Usually, you can watch the screen along with the technologist.
  3. 3D ultrasounds may take up to an hour. If we detect any abnormalities in the fetus, we coordinate for you to receive follow-up care with any necessary specialists. 

Specialized ultrasound

A specialized ultrasound also creates a three-dimensional or even four-dimensional image of the fetus. With a specialized ultrasound, we can also evaluate the:

  • Amniotic fluid
  • Placenta
  • Umbilical cord

The process for a specialized ultrasound is similar to a 3D ultrasound. If needed, we coordinate any sub-specialty appointments for you to receive the care you need.