Ultrasound can be a special part of pregnancy—it’s the first time you get to “see” your baby! Depending on when it’s done and your baby’s position, you may be able to see his hands, legs and other body parts. You may be able to tell if your baby’s a boy or a girl, so be sure to tell your provider if you don’t want to know!
Most women get an ultrasound at 18 to 20 weeks of pregnancy. You may get a first-trimester ultrasound (called an early ultrasound) to confirm your pregnancy (make sure you’re pregnant) and find out your due date.
What are some reasons for having an ultrasound?
Your health care provider uses ultrasound to check your baby’s growth and development and to help estimate your baby’s due date. Ultrasound checks for several things, including:
- Your baby’s age and growth. This helps your provider figure out your due date.
- Your baby’s heartbeat, muscle tone and movement
- Your baby’s overall development
- Multiple pregnancy (twins, triplets or more)
- Birth defects, like spina bifida or Down syndrome
- Pregnancy complications, including miscarriage and ectopic pregnancy
Are there different kinds of ultrasound?
Yes. The kind you get depends on what your provider is checking for and how far along you are in pregnancy. All ultrasounds use a tool called a transducer that uses sound waves to create pictures of your baby on a computer.
The most common kinds of ultrasound are:
- Transabdomial ultrasound. When you hear about ultrasound during pregnancy, it’s most likely this kind. Your provider moves the transducer across your belly. To get a better picture, he covers your belly with a thin layer of gel. This helps the sound waves move more easily. The ultrasound takes about 20 minutes. You may need to have a full bladder during the test. This prevents pockets of air in your bladder from affecting the picture. Ultrasound is painless, but having a full bladder may be uncomfortable.
- Transvaginal ultrasound. This kind is done in the vagina (birth canal). It also takes about 20 minutes. For this test, your bladder needs to be empty or just partly full. The ultrasound is painless, but you may feel some pressure from the transducer.
In special cases, your provider may get more information using other kinds of ultrasound, like:
- Doppler ultrasound. This is used to check a baby’s blood flow if he’s not growing normally.
- 3-D ultrasound. This takes thousands of pictures at once. It makes a 3-D image that’s almost as clear as a photograph.
- 4-D ultrasound. This is like a 3-D ultrasound, but it also shows your baby’s movements.
Does ultrasound have any risks?
Ultrasound is safe for you and your baby when done by your health care provider. Because ultrasound uses sound waves instead of radiation, it’s safer than X-rays. Providers have used ultrasound for more than 30 years, and they have not found any dangerous risks.
If your pregnancy is healthy, ultrasound is good at ruling out problems, but not as good at finding them. It may miss some birth defects. Sometimes, a routine ultrasound may suggest that there is a birth defect when there really isn’t one. While follow-up tests often show that the baby is healthy, false alarms can cause worry for parents.
You may know of some places, like stores in a mall, that aren’t run by doctors or other medical professionals that offer “keepsake” 3-D or 4-D ultrasound pictures or videos for parents. The American College of Obstetricians and Gynecologists, the Food and Drug Administration and the American Institute of Ultrasound in Medicine do not recommend these non-medical ultrasounds. The people doing them may not have medical training and may give you wrong or even harmful information.
What happens after an ultrasound?
For most women, ultrasound shows that the baby is growing normally. If your ultrasound is normal, just be sure to keep going to your prenatal checkups.
Sometimes, ultrasound may show that you and your baby need special care. For example, if the ultrasound shows your baby has a heart problem, she may be able to be treated in the womb before birth. If the ultrasound shows certain birth defects or that your baby is breech (feet-down instead of head-down), you may need a cesarean section (c-section).
No matter what an ultrasound shows, talk to your provider about the best care for you and your baby.
The March of Dimes has partnered with the American Institute of Ultrasound Medicine, Johns Hopkins University and Parents.com to create a unique peak into a baby's development inside the womb. These images reveal the details of a baby's growth from a collection of cells to a full-term newborn.
Last reviewed June 2012