Sign Up Now For HEALTHbeat Our FREE E-mail Newsletter Sign up for our FREE email newsletter and receive a FREE report, Living to 100: What's the secret? You'll receive weekly briefings with health information you can trust from the doctors at Harvard Medical School. [ Close Window ]

• Harvard Health Publications • Order the Book • Contact Us

Sign up for our free e-mail newsletter, HEALTHbeat.   Email address:     Incontinence Weight Loss Prostate Disease Vitamins and Minerals Aching Hands See All Titles Common Medical Conditions Wellness & Prevention Emotional Well Being & Mental Health Women’s Health Men’s Health Heart & Circulatory Health   contact us		Fetal Ultrasound What is the test? How do I prepare for the test? What happens when the test is performed? What risks are there from the test? Must I do anything special after the test is over? How long is it before the result of the test is known? View other tests What is the test? Ultrasound is a painless way to show a fetus in the uterus. The test uses sound waves and a type of sonar detection system to generate a black-and-white moving picture on a TV screen. Fetal ultrasound is useful for determining your pregnancy due date and evaluating the health of the baby and its position. It can show some but not all birth defects (for example, it can show some cases of spina bifida but cannot diagnose Down syndrome). It is also useful for diagnosing twins and can sometimes show the sex of your baby. Back to top > How do I prepare for the test? Early in the pregnancy, you may be asked to drink several glasses of water an hour before the ultrasound so that the uterus can be seen more clearly (a full bladder moves the intestines out of the way). Later in the pregnancy, the uterus has grown sufficiently in size so that this is not necessary. Back to top > What happens when the test is performed? You lie on your back on a table for the test. A technician or doctor first squirts some clear jelly onto your lower abdomen to help the ultrasound sensor slide around easily, and then places the sensor against your skin. The sensor looks like a microphone. When the sensor is in place, a picture appears on a TV screen, and the technician or doctor moves the sensor back and forth on your abdomen to see the fetus from many different views. Depending on the age of the fetus, the heartbeat, movement of arms and legs, and many of the internal organs may be seen. Back to top > What risks are there from the test? There are no risks to either the mother or the fetus from ultrasound. Back to top > Must I do anything special after the test is over? The jelly is wiped off. There are no side effects from the test. Back to top > How long is it before the result of the test is known? Depending on whether the person doing the test is a doctor or a technician, you might be able to get a few results of your test immediately. The test is recorded on a videotape; a radiologist can review the tape and report to your doctor, a process that might take a day or two. Back to top > View other tests
		Click to enlarge Medical Tests: A Practical Guide to Common Tests Are you the type of person who panics when sent for even the most routine medical test? Medical Tests: A Practical Guide to Common Tests provides you with information about common screening and diagnostic medical tests so that you can breathe easier. You’ll learn why the test is needed, how to prepare for it, what happens during the test, and so much more. Now you can go in prepared!. Read more
		©2000–2006 President & Fellows of Harvard College

Close window