What is a fetal ultrasound?

A fetal ultrasound, also commonly referred to as a sonogram, uses high-frequency sound waves and a transducer probe to produce images of a baby inside the uterus. This imaging test may be used to evaluate your baby’s growth and development. In some cases, a fetal ultrasound is used to confirm a diagnosis or evaluate suspected problems with the baby or mom.

Types of fetal ultrasound include:

  • Standard ultrasound
    A standard ultrasound will use sound waves to generate two-dimensional images that project on the computer screen.
  • Doppler ultrasound
    A doppler ultrasound may be ordered if your doctor wants to evaluate the movement of blood between the baby and the placenta, through the baby’s umbilical cord or in the baby’s heart.
  • 3-D ultrasound
    A 3-D ultrasound is able to produce lifelike images of your unborn baby. An electronic transducer is moved over your abdomen and sends sound waves through the skin, muscle, bone and fluids. The transducer translates the images into an image you can see on a computer screen or television monitor.

Who is a candidate for a fetal ultrasound?

Most women have their first ultrasound during their first trimester of pregnancy to confirm the pregnancy and the approximate date the embryo was conceived. In uncomplicated pregnancies, the next ultrasound is typically a more comprehensive test in the second trimester. If you are classified as “high-risk,” you may need more frequent ultrasounds during the second and third trimesters.

Your doctor may order a fetal ultrasound to:

  • Confirm you are pregnant and identify the location where the embryo has implanted.
  • Determine the approximate time when the baby was conceived. This is important, so your doctor can track your baby’s progress throughout gestation.
  • Determine how many babies are present.
  • Understand how well your baby is growing. An ultrasound can monitor your baby’s heart rate, breathing rate and movement.
  • Examine the condition of the placenta and amniotic fluid levels.
  • Find or confirm birth defects in your child.
  • Determine fetal position prior to delivery – a fetal ultrasound can help your doctor see if the baby’s head is positioned downward so the doctor can develop an appropriate delivery plan for you.
  • Evaluate and potentially determine the cause of complications such as bleeding during pregnancy.

What are the risks of a fetal ultrasound?

Although fetal ultrasound is generally safe, it should only be ordered by your doctor for medical reasons. Your doctor should use the lowest ultrasound energy level possible.

What to expect during a fetal ultrasound?

A fetal ultrasound is typically performed in an outpatient setting. What to expect will differ based on what type of fetal ultrasound you are having.

  • Transvaginal fetal ultrasound
    If you are having a transvaginal ultrasound, you will disrobe from the waist down. You will lie on an exam table with your feet in stirrups. When in position, your technician will insert a lubricated ultrasound probe into the vagina and move the probe around to capture images in various locations. When all necessary photos are taken, the probe will be removed.
  • Transabdominal fetal ultrasound
    During a transabdominal fetal ultrasound, you may not need to disrobe but will need to pull your shirt up and pull the waist line of your pants down a bit. You will lie on an exam table, and your ultrasound technician will place a clear gel on your belly. The tech will then move the transducer wand over the lower abdomen where the baby resides. Your tech will take a series of images and measurements to help your doctor evaluate the baby.

Recovery from a fetal ultrasound

In most cases, you will go home after a fetal ultrasound. If there are complications or abnormalities in the ultrasound, your doctor will give you specific instructions.

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