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Fetal ultrasound is a test done during pregnancy that uses reflected sound waves. It produces a picture of the baby (fetus), the organ that supports the fetus (placenta), and the liquid that surrounds the fetus (amniotic fluid). The picture is displayed on a TV screen. It may be in black and white or in color. The pictures are also called a sonogram, an echogram, or a scan. They may be saved as part of your baby's record.
Fetal ultrasound can be done two ways. In a transabdominal ultrasound, a small handheld device called a transducer is moved over your belly. In a transvaginal ultrasound, a transducer is put into your vagina.
Fetal ultrasound is the safest way to check for problems and get details about your fetus. It can find things such as the size and position of the fetus. 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. Sometimes the sex of your fetus can be seen by about the 18th week of pregnancy.
Ultrasound is one of the screening tests that may be done in the first trimester to look for birth defects, such as Down syndrome. The first-trimester screening test uses ultrasound to measure the thickness of the skin at the back of the baby's neck. This screening also includes blood tests that measure the levels of two substances that may be related to birth defects.
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Fetal ultrasound is done to learn about the health of your fetus. Different details can be learned at different times during your pregnancy.
Transvaginal ultrasound is most often done early in a pregnancy to check the age of the fetus. It may also be done if your doctor thinks you may have an ectopic pregnancy. It is sometimes done late in pregnancy to find the location of the placenta. And it may be done in a high-risk pregnancy to check the length of the cervix.
You may need a full bladder for the test. If so, you will be asked to drink water or other liquids just before the test. You will be asked not to urinate before or during the test. In most cases, women in the third trimester do not need to have a full bladder.
For a transvaginal fetal ultrasound, the vaginal transducer is usually covered with a latex sleeve and a lubricant, such as K-Y Jelly. If you are allergic to latex, tell the health professional before you have the test.
Talk to your doctor if you have any concerns about the need for the ultrasound, its risks, how it will be done, or what the results will mean. To help you understand the importance of this test, fill out the medical test information form( What is a PDF document? ).
Most often, a fetal ultrasound is done by an ultrasound technologist. But it may be done by a radiologist or obstetrician. Fetal ultrasound can be done in a doctor's office, hospital, or clinic.
You may not need to remove your clothes for this test. You can lift your shirt and push down your skirt or pants. If you are wearing a dress, you will get a cloth or paper covering to use during the test.
The test takes about 30 to 60 minutes. When it is finished, the gel is cleaned off your skin. You can urinate as soon as the test is done.
Ultrasound techs are trained to gather images of your fetus. But they can't tell you if it looks normal or not. Your doctor will share this information with you after the ultrasound images have been reviewed by a radiologist or perinatologist.
This test takes about 15 to 30 minutes.
During a transabdominal ultrasound, you may have a feeling of pressure in your bladder. The gel may feel cool when it is first put on your belly. You will feel a light pressure when the transducer is passed over your belly.
Normally a transvaginal ultrasound does not cause discomfort. You may feel a light pressure when the transducer is moved in your vagina.
There are no known risks linked with a fetal ultrasound, either to the mother or fetus.
"Keepsake video operations" are ultrasound centers that sell ultrasound videos as your baby's first photo. The U.S. Food and Drug Administration (FDA) does not recommend ultrasounds for this reason. It recommends ultrasounds only to obtain medical information about a fetus. Keepsake centers may use the ultrasound machine at higher energy levels and for longer times than needed in order to get a "good picture."
Fetal ultrasound is a test done during pregnancy that uses reflected sound waves. It produces a picture of the baby (fetus), the organ that supports the fetus (placenta), and the liquid that surrounds the fetus (amniotic fluid).
You may not get details about the test right away. Full results are usually available in 1 or 2 days.
Many conditions can affect fetal ultrasound results. Your doctor will discuss any abnormal results with you in relation to your past health.
You may not be able to have the test, or the results may not be helpful, if:
Other Works Consulted
American College of Obstetricians and Gynecologists (2009, reaffirmed 2014). Ultrasonography in pregnancy. ACOG Practice Bulletin No. 101. Obstetrics and Gynecology, 113(2): 451–461.
Chernecky CC, Berger BJ (2008). Laboratory Tests and Diagnostic Procedures, 5th ed. St. Louis: Saunders.
Fischbach F, Dunning MB III (2015). A Manual of Laboratory and Diagnostic Tests, 9th ed. Philadelphia: Wolters Kluwer Health.
Current as of: May 29, 2019
Author: Healthwise StaffMedical Review: Sarah A. Marshall, MD - Family MedicineE. Gregory Thompson, MD - Internal MedicineKathleen Romito, MD - Family MedicineAdam Husney, MD - Family MedicineWilliam M. Gilbert, MD - Maternal and Fetal MedicineFemi Olatunbosun, MB, FRCSC, FACOG - Obstetrics and Gynecology, Reproductive Endocrinology
Current as of:
May 29, 2019
Medical Review:Sarah A. Marshall, MD - Family Medicine & E. Gregory Thompson, MD - Internal Medicine & Kathleen Romito, MD - Family Medicine & Adam Husney, MD - Family Medicine & William M. Gilbert, MD - Maternal and Fetal Medicine & Femi Olatunbosun, MB, FRCSC, FACOG - Obstetrics and Gynecology, Reproductive Endocrinology
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