Skip to content
My WebMD Sign In, Sign Up

Health & Pregnancy

Font Size
A
A
A

Fetal Ultrasound

Fetal ultrasound is a test done during pregnancy that uses reflected sound waves to produce a picture of a fetus camera.gif, the organ that nourishes the fetus (placenta), and the liquid that surrounds the fetus (amniotic fluid). The picture is displayed on a TV screen and may be in black and white or in color. The pictures are also called a sonogram, echogram, or scan, and they may be saved as part of your baby's record.

Fetal ultrasound is the safest way to check for problems and get information about your fetus, such as its size and position. It does not use X-rays or other types of radiation that may harm your fetus. It can be done as early as the 5th week of pregnancy. The sex of your fetus can sometimes be determined by about the 18th week of pregnancy.

Pregnancy: Should I Have an Early Fetal Ultrasound?

A combination of screening tests using ultrasound may be done in the first trimester to look for birth defects, such as Down syndrome. The first-trimester screening test uses an ultrasound measurement of the thickness of the skin at the back of the baby's neck (nuchal translucency) and the blood levels of free beta-HCG and a protein called pregnancy-associated plasma protein A (PAPP-A) to check for problems.

Health Tools

Health Tools help you make wise health decisions or take action to improve your health.

dplink.gif

Decision Points focus on key medical care decisions that are important to many health problems.

Pregnancy: Should I Have an Early Fetal Ultrasound?

Why It Is Done

Fetal ultrasound camera.gif is done to learn about the health of the fetus. Different information is gained at different times (trimesters) during your pregnancy.

  • 1st-trimester fetal ultrasound is done to:
    • Determine how your pregnancy is progressing.
    • Find out if you are pregnant with more than 1 fetus.
    • Estimate the age of the fetus (gestational age).
    • Estimate the risk of a chromosome defect, such as Down syndrome.
    • Check for birth defects that affect the brain or spinal cord.
  • 2nd-trimester fetal ultrasound is done to:
    • Estimate the age of the fetus (gestational age).
    • Look at the size and position of the fetus, placenta, and amniotic fluid.
    • Determine the position of the fetus, umbilical cord, and the placenta during a procedure, such as an amniocentesis camera.gif or umbilical cord blood sampling.
    • Detect major birth defects, such as a neural tube defect or heart problems.
  • 3rd-trimester fetal ultrasound is done to:
    • Make sure that a fetus is alive and moving.
    • Look at the size and position of the fetus, placenta, and amniotic fluid.

Transvaginal ultrasound is generally done early in a pregnancy to determine fetal age or to detect a suspected ectopic pregnancy camera.gif. It is occasionally done late in pregnancy to determine the location of the placenta or in a high-risk pregnancy to monitor the length of the cervix camera.gif.

1 | 2 | 3 | 4

WebMD Medical Reference from Healthwise

Last Updated: June 18, 2012
This information is not intended to replace the advice of a doctor. Healthwise disclaims any liability for the decisions you make based on this information.

Pregnancy Week-By-Week Newsletter

Delivered right to your inbox, get pictures and facts on
what to expect each week of your pregnancy.

Today on WebMD

Woman smiling as she reads pregnancy test
Slideshow
pregnant woman with salad
Quiz
 
pregnant in thought
Article
babyapp
NEW
 

slideshow fetal development
Slideshow
pregnancy first trimester warning signs
Article
 
What Causes Bipolar
Video
Woman trying on dress in store
Slideshow
 

pregnant woman
Article
Close up on eyes of baby breastfeeding
Video
 
healthtool pregnancy calendar
Tool
eddleman prepare your body pregnancy
Video