Ultrasound pregnancy: MedlinePlus Medical Encyclopedia
A pregnancy ultrasound is an imaging test that uses sound waves to create a picture of how a baby is developing in the womb. It is also used to check the female pelvic organs during pregnancy.Watch this video about:UltrasoundHow the Test is Performed
To have the procedure:You will lie on your back on an exam table.The person performing the test will spread a clear, water-based gel on your belly and pelvis area. A handheld probe will then be moved the area. The gel helps the probe transmit sound waves.These waves bounce off the body structures, including the developing baby, to create a picture on the ultrasound machine.
In some cases, a pregnancy ultrasound may be done by placing the probe into the vagina.How to Prepare for the Test
You will need to have a full bladder to get the best ultrasound image. You may be asked to drink 2 to 3 glasses of liquid an hour before the test. DO NOT urinate before the procedure.How the Test will Feel
There may be some discomfort from pressure on the full bladder. The conducting gel may feel slightly cold and wet. You will not feel the ultrasound waves.Why the Test is Performed
An ultrasound may be done to determine if there is a problem with the pregnancy, how far along the pregnancy is, or to take measurements and screen for potential problems.
A pregnancy ultrasound may be done during the first 12 weeks of pregnancy to:Confirm a normal pregnancyDetermine the baby's ageLook for problems, such as ectopic pregnancies or the chances for a miscarriageDetermine the baby's heart rateLook for multiple pregnancies (such as twins and triplets)Identify problems of the placenta, uterus, cervix, and ovariesLook for findings that might indicate an increased risk for Down syndrome
A pregnancy ultrasound may also be done in the second and third trimesters to:Determine the baby's age, growth, position, and sometimes genderIdentify any problems with how the fetus is developingLook for twins or triplets. Look at the placenta, amniotic fluid, and pelvis
Some centers are now performing a pregnancy ultrasound around 9 to 13 weeks of pregnancy to look for signs of Down syndrome or other problems in the developing baby. This test is often combined with blood tests to improve the accuracy of results.
How many ultrasounds you will need depends on whether a previous scan or blood test has detected problems that require follow-up testing.Normal Results
The developing baby, placenta, amniotic fluid, and surrounding structures appear normal for the gestational age.
Note: Normal results may vary slightly. Talk to your doctor about the meaning of your specific test results.What Abnormal Results Mean
Abnormal ultrasound results may be due to some of the following conditions:Birth defectsEctopic pregnancyPoor growth of a baby while in the mother's wombMultiple pregnanciesMiscarriageProblems with the baby's position in the wombProblems with the placenta, including placenta previa and placental abruptionToo little amniotic fluidToo much amniotic fluid (polyhydramnios)Tumors of pregnancy, including gestational trophoblastic diseaseOther problems with the ovaries, uterus, and remaining pelvic structures Risks
Current ultrasound techniques appear to be safe. Ultrasound does not involve radiation. Alternative Names
Pregnancy sonogram; Obstetric ultrasonography; Obstetric sonogram; Ultrasound - pregnancy; IUGR - ultrasound; Intrauterine growth - ultrasound; Polyhydramnios - ultrasound; Oligohydramnios - ultrasound; Placenta previa - ultrasound; Multiple pregnancy - ultrasound; Vaginal bleeding during pregnancy - ultrasound; Fetal monitoring - ultrasoundImages Ultrasound in pregnancy Ultrasound, normal fetus - abdomen measurements Ultrasound, normal fetus - arm and legs Ultrasound, normal placenta - Braxton Hicks Ultrasound, normal fetus - face Ultrasound, normal fetus - femur measurement Ultrasound, normal fetus - foot Ultrasound, normal fetus - head measurements Ultrasound, normal fetus - heartbeat Ultrasound, ventricular septal defect - heartbeat Ultrasound, normal fetus - arms and legs Ultrasound, normal relaxed placenta Ultrasound, normal fetus - profile view Ultrasound, normal fetus - spine and ribs Ultrasound, color - normal umbilical cord Ultrasound, normal fetus - ventricles of brain Prenatal ultrasound - series 3D ultrasound References
Richards DS. Obstetrical ultrasound: imaging, dating, and growth. In: Gabbe SG, Niebyl JR, Simpson JL, et al, eds. Obstetrics: Normal and Problem Pregnancies. 6th ed. Philadelphia, PA: Elsevier Saunders; 2012:chap 9.
Tayal VS. Emergency ultrasound. In Marx JA, Hockberger RS, Walls RM, eds. Rosen's Emergency Medicine: Concepts and Clinical Practice. 8th ed. Philadelphia, PA: Elsevier Saunders; 2014:chap 196.
Wolf RB. Abdominal imaging. In: Creasy RK, Resnick R, Iams JD, Lockwood CJ, Moore TR, Greene MF, eds. Creasy and Resnik's Maternal-Fetal Medicine: Principles and Practice. 7th ed. Philadelphia, PA: Elsevier Saunders; 2014:chap 24.Read More Ectopic pregnancy Intrauterine growth restriction Polyhydramnios Review Date 4/5/2016
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