Fetal Ultrasound

Fetal ultrasound is a test done during pregnancy that uses reflected sound waves to produce a picture of a Reference fetus Opens New Window, the organ that nourishes the fetus (Reference placenta Opens New Window), and the liquid that surrounds the fetus (Reference amniotic fluid Opens New Window). 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 Reference X-rays Opens New Window 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. For more information, see:

Opens New Window Pregnancy: Should I Have an Early Fetal Ultrasound? Opens New Window

A combination of screening tests using ultrasound may be done in the first trimester to look for birth defects, such as Reference Down syndrome Opens New Window. The Reference 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.

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