Click here to return to the LMHS Home Page

 

Print-Friendly
Bookmarks

Ultrasound

Pregnancy sonogram; Obstetric ultrasonography; Obstetric sonogram; Ultrasound - pregnancy

 

A pregnancy ultrasound is an imaging test that uses sound waves to create a picture of how a baby is developing in the womb. It is also used to check the female pelvic organs during pregnancy.

 

How the Test is Performed

 

To have the procedure:

  • You will lie on your back on an exam table.
  • The person performing the test will spread a clear, water-based gel on your belly and pelvis area. A hand-held probe will then be moved the area. The gel helps the probe transmit sound waves.
  • These waves bounce off the body structures, including the developing baby, to create a picture on the ultrasound machine.

In some cases, a pregnancy ultrasound may be done by placing the probe into the vagina.

 

How to Prepare for the Test

 

You will need to have a full bladder to get the best ultrasound image. You may be asked to drink 2 to 3 glasses of liquid an hour before the test. Do not urinate before the procedure.

 

How the Test will Feel

 

There may be some discomfort from pressure on the full bladder. The conducting gel may feel slightly cold and wet. You will not feel the ultrasound waves.

 

Why the Test is Performed

 

An ultrasound may be done to determine if there is a problem with the pregnancy, how far along the pregnancy is, or to take measurements and screen for potential problems.

Talk to your health care provider to determine the most appropriate scanning schedule for you.

A pregnancy ultrasound may be done during the first 12 weeks of pregnancy to:

  • Confirm a normal pregnancy
  • Determine the baby's age
  • Look for problems, such as ectopic pregnancies or the chances for a miscarriage
  • Determine the baby's heart rate
  • Look for multiple pregnancies (twins, triplets, etc.)
  • Identify problems of the placenta, uterus, cervix, and ovaries
  • Look for findings that might indicate an increased risk for Down syndrome

A pregnancy ultrasound may also be done in the second and third trimesters to:

  • Determine the baby's age, growth, position, and sometimes gender
  • Identify any problems with how the fetus is developing
  • Look for twins, triplets, etc.
  • Look at the placenta, amniotic fluid, and pelvis

Some centers are now performing a pregnancy ultrasound around 9 - 13 weeks of pregnancy to look for signs of Down syndrome or other problems in the developing baby. This test is often combined with blood tests to improve the accuracy of results.

How many ultrasounds you will need depends on whether a previous scan or blood test has detected problems that require follow-up testing.

 

Normal Results

 

The developing baby, placenta, amniotic fluid, and surrounding structures appear normal for the gestational age.

Note: Normal results may vary slightly. Talk to your doctor about the meaning of your specific test results.

 

What Abnormal Results Mean

 

Abnormal ultrasound results may be due to some of the following conditions:

  • Birth defects
  • Ectopic pregnancy
  • Poor growth of a baby while in the mother's womb
  • Multiple pregnancies
  • Miscarriage
  • Problems with the baby's position in the womb
  • Problems with the placenta, including placenta previa and placental abruption
  • Too little amniotic fluid
  • Too much amniotic fluid (polyhydramnios)
  • Tumors of pregnancy, including gestational trophoblastic disease
  • Other problems with the ovaries, uterus, and remaining pelvic structures

 

Risks

 

Current ultrasound techniques appear to be safe. Ultrasound does not involve radiation.

 

 

References

Richards DS. Obstetrical ultrasound: Imaging, dating, and growth. In: Gabbe SG, Niebyl JR, Simpson JL, et al, eds. Obstetrics: Normal and Problem Pregnancies. 6th ed. Philadelphia, PA: Saunders Elsevier; 2012:chap 9.

Taval VS. Emergency ultrasound. In Marx JA, Hockberger RS, Walls RM, et al, eds. Rosen's Emergency Medicine: Concepts and Clinical Practice. 8th ed. Philadelphia, PA: Mosby Elsevier; 2013:chap 196.

BACK TO TOPText only

 
  • Ultrasound in pregnancy

    Ultrasound in pregnancy

    illustration

  • Ultrasound, normal fetus - abdomen measurements

    Ultrasound, normal fetus...

    illustration

  • Ultrasound, normal fetus - arm and legs

    Ultrasound, normal fetus...

    illustration

  • Ultrasound, normal placenta - Braxton Hicks

    Ultrasound, normal place...

    illustration

  • Ultrasound, normal fetus - face

    Ultrasound, normal fetus...

    illustration

  • Ultrasound, normal fetus - femur measurement

    Ultrasound, normal fetus...

    illustration

  • Ultrasound, normal fetus - foot

    Ultrasound, normal fetus...

    illustration

  • Ultrasound, normal fetus - head measurements

    Ultrasound, normal fetus...

    illustration

  • Ultrasound, normal fetus - heartbeat

    Ultrasound, normal fetus...

    illustration

  • Ultrasound, normal fetus - heartbeat

    Ultrasound, normal fetus...

    illustration

  • Ultrasound, normal fetus - arms and legs

    Ultrasound, normal fetus...

    illustration

  • Ultrasound, normal relaxed placenta

    Ultrasound, normal relax...

    illustration

  • Ultrasound, normal fetus - profile view

    Ultrasound, normal fetus...

    illustration

  • Ultrasound, normal fetus - spine and ribs

    Ultrasound, normal fetus...

    illustration

  • Ultrasound, color - normal umbilical cord

    Ultrasound, color - norm...

    illustration

  • Ultrasound, normal fetus - ventricles of brain

    Ultrasound, normal fetus...

    illustration

  • Ultrasound - series

    Ultrasound - series

    Presentation

  •  
  • 3D ultrasound

    3D ultrasound

    illustration

    • Ultrasound in pregnancy

      Ultrasound in pregnancy

      illustration

    • Ultrasound, normal fetus - abdomen measurements

      Ultrasound, normal fetus...

      illustration

    • Ultrasound, normal fetus - arm and legs

      Ultrasound, normal fetus...

      illustration

    • Ultrasound, normal placenta - Braxton Hicks

      Ultrasound, normal place...

      illustration

    • Ultrasound, normal fetus - face

      Ultrasound, normal fetus...

      illustration

    • Ultrasound, normal fetus - femur measurement

      Ultrasound, normal fetus...

      illustration

    • Ultrasound, normal fetus - foot

      Ultrasound, normal fetus...

      illustration

    • Ultrasound, normal fetus - head measurements

      Ultrasound, normal fetus...

      illustration

    • Ultrasound, normal fetus - heartbeat

      Ultrasound, normal fetus...

      illustration

    • Ultrasound, normal fetus - heartbeat

      Ultrasound, normal fetus...

      illustration

    • Ultrasound, normal fetus - arms and legs

      Ultrasound, normal fetus...

      illustration

    • Ultrasound, normal relaxed placenta

      Ultrasound, normal relax...

      illustration

    • Ultrasound, normal fetus - profile view

      Ultrasound, normal fetus...

      illustration

    • Ultrasound, normal fetus - spine and ribs

      Ultrasound, normal fetus...

      illustration

    • Ultrasound, color - normal umbilical cord

      Ultrasound, color - norm...

      illustration

    • Ultrasound, normal fetus - ventricles of brain

      Ultrasound, normal fetus...

      illustration

    • Ultrasound - series

      Ultrasound - series

      Presentation

    •  
    • 3D ultrasound

      3D ultrasound

      illustration

    A Closer Look

     

      Self Care

       

        Tests for Ultrasound

         
         

        Review Date: 3/11/2014

        Reviewed By: Susan Storck, MD, FACOG, Chief, Eastside Department of Obstetrics and Gynecology, Group Health Cooperative of Puget Sound, Bellevue, WA; Clinical Teaching Faculty, Department of Obstetrics and Gynecology, University of Washington School of Medicine, Seattle, WA. Also reviewed by David Zieve, MD, MHA, Isla Ogilvie, PhD, and the A.D.A.M. Editorial team.

        The information provided herein should not be used during any medical emergency or for the diagnosis or treatment of any medical condition. A licensed medical professional should be consulted for diagnosis and treatment of any and all medical conditions. Links to other sites are provided for information only -- they do not constitute endorsements of those other sites. © 1997- A.D.A.M., Inc. Any duplication or distribution of the information contained herein is strictly prohibited.
        adam.com

         
         
         

         

         

        A.D.A.M. content is best viewed in IE9 or above, Firefox and Google Chrome browser.