Ultrasound uses sound waves to create a visual image of your baby. A transducer, which is a specialized plastic wand, sends out high frequency sound waves into your abdomen for a few seconds. The sound waves don't hurt the baby, and they cannot be felt or heard by humans. For the rest of the scan, the transducer "listens" for the sound to return. A computer interprets the sound and creates an image of your baby on the screen.
To help you understand your ultrasound, we've compiled and answered a number of frequently- asked questions.
Our answers to your questions cannot replace a discussion between you and your physician, so you should feel comfortable talking with your doctor or health care provider if you still have questions about your ultrasound exam.
Frequently Asked Questions
Will ultrasound detect chromosomal abnormalities?
Ultrasound cannot directly detect abnormal fetal chromosomes. However, it can be used for safely guiding amniocentesis procedures or to detect structural anomalies that suggest an increased risk for abnormal chromosomes.
Will the ultrasound show if my baby has Down syndrome?
No. Ultrasound is very poor at detecting Down syndrome.
Can you determine the sex of my baby?
The sex of your baby can usually be determined accurately beginning at 16 weeks if your baby is in a good position or if there is enough fluid around the baby's bottom.
How accurate is sex determination?
It is usually quite accurate. However, errors can occur if the male genitalia are small or the female clitoris is temporarily enlarged, which is a normal occurrence.
Can I have a picture and video of the ultrasound?
We will give you a clearly labeled picture of your baby and will show you your baby at the end of the exam. We do not allow videotaping.
What if I need to cancel my appointment?
If you need to cancel or cannot arrive by your appointment time, please call the department as soon as possible at 248-898-2070 (for Royal Oak, Troy, or Grosse Pointe) or 313-593-7521 (for Dearborn).
Can I have my family present?
- During a screening examination, up to three family members may watch part of the examination.
- Please have someone with you to supervise your children under 5 years old.
- During targeted examinations, fetal echocardiograms, and amniocentesis, one support person may be present. No children please.
At Dearborn:
- During a screening examination, one support person (adult) may be present for your examination.
- If you need to bring a child to your appointment, please bring another adult who can supervise your child so that we can address your care without distraction. Children under 13 years of age will need adult supervision in the waiting room.
When will I get the results?
Your physician should have your results within a day.
How long does an ultrasound take?
A screening exam usually takes 20 to 30 minutes. Targeted exams may last 60 to 90 minutes.
Why do I need to drink fluid?
Air transmits sound very poorly. The air in your bowel stops the sound waves from entering the uterus and visualizing your baby. When your bladder is filled with fluid, it pushes the air-filled bowel out of the way. Since fluid transmits sound very well, it provides an acoustic window into your uterus. It also allows the sonographer to see the lower part of your uterus and your cervix.
Who performs the scan?
- A sonographer performs the scan from beginning to end.
- Corewell Health's sonographers are trained in sonography. They pass a special registry test, and our physicians provide them with additional training. They only perform ultrasounds on pregnant women, so they are very experienced in the type of ultrasound you will be having.
- A physician interprets the results, and a report will be sent to your obstetrician.
How is an ultrasound performed?
- You will be asked to lie on your back or on your side. You will not need to take off your clothes, but we will have to expose your abdominal area so the transducer can touch your skin directly.
- Wear a skirt or pants so that they can be pulled down far enough to expose your entire abdomen. You will also need to pull your shirt up to uncover your abdomen. We will tuck a towel into the top of your skirt or pants
- The sonographer will place warm gel on your abdomen. This gel helps transmit sound waves and allows the transducer to slide easily across the abdomen.
- Empty your bladder approximately 90 minutes before the exam.
- You should drink two glasses (16 ounces) of water one hour before the exam is scheduled to begin.
- A full bladder is essential. It provides an acoustic window into the pelvis. Please wear a two-piece outfit so that you will not need to disrobe.
Can ultrasound affect my baby?
- There is no scientific evidence that ultrasound can harm your baby.
- Several long-term studies have evaluated the effect of ultrasound on babies. One study of children who had prenatal scans showed no difference in their psychological, intellectual or physical development when compared to children who were not scanned. Other studies did not find differences in either growth or hearing.
Did You Know?
- For a typical 30-minute scan, you actually receive ultrasound for only 1.7 seconds. The remainder of the time the transducer is listening for the sound.
Appointments
Your doctor's office may schedule your appointment for you, but if you need to make, change or cancel an appointment, call 248-898-2070 (for Royal Oak, Troy, or Grosse Pointe) or 313-593-7521 (for Dearborn).