What is a fetal ultrasound?
“Fetal ultrasound examination” encompasses several different kinds of imaging tests. Using high-frequency sound waves, ultrasounds safely monitor the health and development of your baby in the womb.
Ultrasounds are used early in pregnancy to confirm the presence of multiple fetuses or to look for any irregularities of the uterus or ovaries that can affect your pregnancy. Later, a 3D ultrasound might be ordered by your OB/GYN to see more detail. If your OB/GYN suspects complications that might affect your delivery, increase the risk of preterm labor, or affect your child’s health after delivery, they may order a 4D ultrasound to view your baby in real time.
How are ultrasounds used to monitor the health of a developing fetus?
A fetal ultrasound examination or sonogram uses high-frequency sound waves to create images of the fetus, placenta, and surrounding amniotic fluid. This provides real-time information about your baby’s growth and development, as well as information about the structures surrounding and nourishing the developing fetus.
When looking at a fetal ultrasound, the basic things that I evaluate include:
- Heart activity and rhythm
- Size and growth pattern
- Fetal presentation (the baby’s position within the uterus, such as breech)
- Placental position
- Amniotic fluid volume around the fetus
- Fetal activity and behavior
- The presence and location of any uterine fibroids
- Length of the cervix
We’ll perform an ultrasound at different points of the pregnancy to monitor fetal growth and to check for different potential problems.
Your first fetal ultrasound
Your first ultrasound is late in your first trimester. The 12-week fetal ultrasound serves multiple diagnositc purposes:
- Calculate accurate gestational age of the fetus.
- Confirm number of fetuses and if they’re sharing a placenta.
- Assess risk of chromosomal abnormalities such as Down syndrome.
This early pregnancy imaging can be done in our office or in the comfort and privacy of your home via our exclusive in-home care option. If your pregnancy remains uncomplicated, the next ultrasound is typically done during the second trimester, when anatomic details (including your baby’s sex) become visible.
The most sophisticated 4D ultrasound machine in the world is only as good as the ability of the technician using it and the doctor interpreting the images.
Your second fetal ultrasound
The fetal anatomy scan is typically performed around 18 to 20 weeks of pregnancy. The fetal anatomy scan or ultrasound evaluates your baby’s anatomy in greater detail in order to closely monitor its development.
Under certain circumstances, an additional study, known as an advanced fetal anatomy ultrasound, may be necessary for a more detailed evaluation of specific organs. A more detailed fetal anatomy scan is indicated if the initial anatomy scan results are abnormal, if you have worrisome exam findings, elevated risk factors for birth defects, or have certain medical conditions that can complicate your pregnancy. Under rare circumstances, highly specialized diagnostic procedures such as amniocentesis or chorionic villus sampling may be considered if there is a concern for a genetic anomaly.
Your third fetal ultrasound
During the late second or early third trimester we’ll perform an ultrasound to assess fetal growth. If there is concern about your baby’s size, we can perform more frequent ultrasounds to measure how your baby is growing over time.
The main measurements taken for a fetal growth ultrasound include:
- Biparietal diameter (BPD) – the distance from one temple to the other
- Head circumference (HC)
- Abdominal circumference (AC)
- Femur length (FL)
The sonographer plots these measurements on a growth chart according to the fetus’s gestational age, and an algorithm calculates the estimated fetal weight (EFW). This prenatal measurement is used to determine whether your baby is smaller, larger, or average weight for its gestational age. This information can be a clue to underlying medical issues and an indicator of your child’s birth weight.
What happens if a fetus is growing too slowly?
If your baby’s weight estimate is below the bottom 10th percentile line on the graph, it is considered small for gestational age (SGA). If the fetal weight is above the top 10th percentile line on the graph, it is deemed large for gestational age (LGA). LGA has been linked to gestational diabetes in the mother. In these cases, third-trimester growth is closely monitored with serial ultrasound measurements.
Fetal growth restriction (FGR) — the baby being too small for gestational age — can be caused by many factors. FGR may only become obvious after two or more fetal growth ultrasounds have been performed.
Other biometry tests can be performed to look for the cause of FGR. For instance, a 3D fetal ultrasound can look at the amount of amniotic fluid surrounding the fetus, or a Doppler ultrasound study can measure the blood flow within the umbilical cord.
Our advanced specialty high-resolution detailed ultrasounds
When necessary, our practice offers more advanced, specialized ultrasound to obtain a more detailed assessment of your fetus. For instance, neurosonography ultrasounds look closely at your baby’s brain and spinal cord to evaluate for birth defects or genetic anomalies. A nuchal translucency study measures the thickness of fluid behind your baby’s neck — which is often larger in babies with Down syndrome.
Our high-resolution fetal ultrasounds allow our healthcare team to evaluate specific organs and determine if your baby is at risk for genetic conditions such as:
- Spina bifida and neural tube defects
- Cleft palate
- Congenital abnormalities of the heart
- Down syndrome
- Genetic anomalies like Trisomy 18 and Trisomy 13
- Skeletal malformations
What happens during a fetal ultrasound exam?
The obstetrical ultrasound is performed during a regular office visit and can be performed either transabdominally or transvaginally, depending on your needs. Most people are familiar with transabdominal ultrasounds; they just involve applying gel to your lower abdomen and moving a transducer across your skin. This exam requires you to come with a semi-full bladder and only takes about 30 to 45 minutes to complete.
A transvaginal study is a little more invasive but obtains a more detailed view of the fetus and surrounding organs. It involves inserting the transducer into the vagina and gently rotating it to get a 360-degree view. You may experience some mild pressure — similar to when you undergo a pelvic exam. There is no special preparation needed for this procedure and it usually takes less than 30 minutes to perform.
If any abnormal findings are detected or suspected, if just for an abundance of caution, I might perform additional testing. In rare cases, we may recommend an antenatal (pre-birth) procedure to address any treatable conditions.
Is all fetal ultrasound technology the same?
No, it is not. As one of Los Angeles’ premier maternal-fetal medicine providers, we use state-of-the-art 4D high-definition ultrasound technology to monitor not just your baby’s development but also to screen for any maternal complications that may affect your pregnancy. Our advanced technology and sonography expertise allows us to diagnose fetal abnormalities as early as 11 to 16 weeks of gestational age — a capacity not available elsewhere in Los Angeles.
Dr. Steve Rad has undergone extensive training in fetal sonography, echocardiography, and the interpretation of early fetal scans under the auspices of the world’s leading specialists in the United Kingdom, Austria, Israel, and the United States. What’s more, he has personally trained our obstetrics sonographer in advanced fetal scanning techniques.
Do I need to be a “high-risk pregnancy” to see Dr. Rad?
Not at all. Dr. Rad welcomes all patients who wish to have personalized prenatal care with close monitoring of mother and child. Whether this is your first pregnancy or your tenth, you are invited to schedule an appointment with us to learn how we can help guide you through your pregnancy and delivery.
Tragically, it doesn’t take much for a pregnancy to escalate from normal to “high risk.” By establishing care with a perinatologist early, you’ll be in good hands should your pregnancy escalate.
Why choose Dr. Steve Rad and the Los Angeles Fetal and Maternal Care Center?
Did you know that all pregnancies in the United States are at risk of becoming high-risk? Even a pregnancy that begins “low-risk” can become high-risk. That is no secret to double-board certified Dr. Steve Rad, an Obstetrician-Gynecologist with sub-specialty training in Maternal-Fetal Medicine / Perinatology.
Dr. Rad has been named a top Maternal-Fetal Medicine specialist in Los Angeles by Los Angeles Magazine for six years in a row.
Dr. Rad has undergone rigorous training with high honors at prestigious, renowned institutions such as the David Geffen School of Medicine at UCLA, USC, Cedars-Sinai Medical Center, and UCSF Medical Center, as well as internationally in London, Austria, Israel, and Africa.
He is passionate about obstetrics and gynecology and uses his proficiency to guide high-risk mothers with prenatal testing, special monitoring, and diligent care during their pregnancy up to and including the birth of their baby.
Dr. Rad and his team understand your health information needs before, during, and after birth. We help you understand your pregnancy, answer all your questions, and give you the emotional support and the means to safely navigate your pregnancy.
Call us at (844) 473-6100 to schedule a consultation. We are currently accepting new patients.
Cedars-Sinai Medical Office Tower – East,
8631 W 3rd St
Los Angeles, California 90048
We are conveniently located for patients throughout Southern California and the Los Angeles area at locations in or near Beverly Hills, Santa Monica, West Los Angeles, West Hollywood, Culver City, Hollywood, Venice, Marina del Rey, Malibu, Manhattan Beach, Newport Beach, Irvine, and Downtown Los Angeles. We also offer in-home prenatal care and a fly-in program for out-of-town and international patients. Dr. Rad even travels to patients who need him throughout the U.S. and around the world.
If you can’t make it to Dr. Rad, he also offers virtual consultations worldwide.