What Is Ultrasound?
]]>Ultrasound]]> uses reflected sound waves instead of ]]>x-rays]]> to create pictures of the internal organs. Ultrasound is a safer alternative to x-ray during pregnancy and is used to view the fetus. Real-time ultrasound is most often used to show the fetal heartbeat and body movements. The procedure is also used to show the growing fetus, the number of fetuses in the uterus, and the position of the fetus and placenta. It is also very helpful in establishing the age of the fetus, that is, the "dates of the pregnancy."
]]>Doppler ultrasound]]> provides sound that can be heard through amplification. It can be used so that the mother and healthcare provider can actually hear the fetal heartbeat.
How Is Ultrasound Used During Pregnancy?
It is not necessary for every pregnant woman to have ultrasound. However, it is an excellent means to determine the age of the fetus The procedure is often used, along with a medical history and physical exams, to detect a problem or monitor a condition. Your healthcare provider will discuss with you the use of ultrasound to monitor your pregnancy.
Ultrasound helps to determine whether the fetus is growing properly. If there is an abnormality, your healthcare provider may be able to help you reduce risks to yourself and the growing fetus. Ultrasound is used to detect:
- The number of fetuses
- The age of the fetus
- The size of the fetus and rate of growth
- The heart rate, breathing, position, and movement of the fetus
- The location of the placenta
- The amount of amniotic fluid in the uterus
- Certain types of birth defects, including some that affect the heart, head, chest, spine, and limbs
Doppler ultrasound is used to:
- Monitor fetal heart rate before or during labor
- Measure the flow of blood within the vessels of the uterus, umbilical cord, and fetus
Vaginal ultrasound is used to:
- Detect an ]]>ectopic pregnancy]]>
- Determine the cause of bleeding or pain
- Detect certain birth defects early in the pregnancy
What Happens During an Ultrasound Exam?
To prepare for the exam, you should wear comfortable clothes. You may be asked to wear a hospital gown. If you're having a vaginal ultrasound, you'll need to remove your clothes from the waist down and cover up with a sheet. Abdominal ultrasound exams require a full bladder because it helps the clinician view the pelvic organs. If this is the case, you will be asked to drink several glasses of water before the exam and not urinate until the exam is over.
With most ultrasound exams, you will lay on the table with your abdominal area exposed. A thin gel will be applied to your abdomen, which improves contact with the transducer. The transducer will be moved along your abdomen, sending out sound waves that are reflected back from the organs and fetus.
Are There Any Risks Associated With Ultrasound?
No harmful effects have been found from ultrasound since it was first used over 40 years ago. There are no known long-term risks for mother or baby. The benefits are that it is accurate and fast in detecting problems and does not involve the use of radiation, drugs, chemicals, or dyes.
American Academy of Family Physicians
American Congress of Obstetricians and Gynecologists
Women's Health Matters
Ultrasonography in pregnancy [practice bulletin]. American College of Obstetricians and Gynecologists. 2004 Dec;58.
Last reviewed January 2009 by ]]>Ganson Purcell Jr., MD, FACOG, FACPE]]>
Please be aware that this information is provided to supplement the care provided by your physician. It is neither intended nor implied to be a substitute for professional medical advice. CALL YOUR HEALTHCARE PROVIDER IMMEDIATELY IF YOU THINK YOU MAY HAVE A MEDICAL EMERGENCY. Always seek the advice of your physician or other qualified health provider prior to starting any new treatment or with any questions you may have regarding a medical condition.
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