Fetal Ultrasound


Relaxed Black couple watching baby ultrasound photo, lying in bed at home; Pregnancy: Fetal Ultrasound

Fetal ultrasound is also known as a sonogram. It’s used to view the fetus inside the uterus. It allows your OB/GYN to check the fetus’s health and development, monitor your pregnancy, and detect any possible health issues.

About Fetal Ultrasound

A fetal ultrasound (or sonogram) is a type of imaging exam that uses sound waves to create images on a screen of your uterus and the fetus.  A device called a transducer sends sound waves through the body. The waves then bounce back off tissues, fluids, and bones, like echoes. The transducer receives these echoes and turns them into images. The images can be viewed as pictures on a video screen.

Why is It Done?

Ultrasounds are done throughout pregnancy for different reasons. How often you get an ultrasound exam depends on factors like how far along in your pregnancy you are and your personal health history.

First Trimester Fetal Ultrasounds

In the first trimester of pregnancy (weeks one to 12), ultrasounds may be done to:

  • Confirm pregnancy
  • Check the fetal heartbeat
  • Determine the gestational age of the baby and estimate a due date
  • Check for multiple pregnancies
  • Examine the placenta, uterus, ovaries, and cervix

Second and Third Trimester Ultrasounds

In the second trimester (12 to 24 weeks) and the third trimester (24 to 40 weeks or birth), a fetal ultrasound may be done to:

  • Screen for birth defects
  • Monitor the fetus’ growth and position (breech, transverse, cephalic, or optimal)
  • Determine the baby’s sex
  • Confirm multiple pregnancies
  • Check the placenta for problems, such as placenta previa (when the placenta covers the cervix) and placental abruption (when the placenta separates from the uterus prior to delivery.
  • Monitor the levels of amniotic fluid
  • Determine if the fetus is getting enough oxygen
  • Diagnose problems with the ovaries or uterus, such as pregnancy tumors
  • Measure the length of the cervix
  • Guide other tests, such as amniocentesis

Types of Fetal Ultrasound

During a fetal ultrasound exam, the transducer is either moved across your abdomen (transabdominal ultrasound) or placed in your vagina (transvaginal ultrasound). The type of ultrasound exam you have depends on what types of images your ob-gyn or other health care professional needs and why the exam is being done.

Transabdominal Ultrasound

A transabdominal fetal ultrasound is done by moving a transducer over your abdomen. A gel is applied to the surface of the abdomen. This improves contact of the transducer with the skin surface. The handheld transducer then is moved along the abdomen to make images

Transvaginal ultrasound

A transvaginal ultrasound may be done to produce a clearer image. This ultrasound is more likely to be used during the early stages of pregnancy when capturing a clear image may be more difficult. For this test, a small ultrasound probe is inserted into the vagina. The probe rests against the back of your vagina while the images are captured.

3-D ultrasound

Unlike a traditional 2-D ultrasound, a 3-D ultrasound allows your doctor to see the width, height, and depth of the fetus and your organs. This ultrasound can be especially helpful in diagnosing any suspected problems during your pregnancy. A 3-D ultrasound follows the same procedure as a standard ultrasound, but it uses a special probe and software to create the 3-D image. It also requires special training for the technician, so it may not be as widely available.


Contact Raleigh OB/GYN Centre

The providers at Raleigh OB/GYN offer a comprehensive list of gynecological and obstetric services to the women of the Raleigh, NC area. If you have questions about fetal ultrasound or any of our other women’s health services, call our office at (919) 876-8225 to make an appointment.