General Ultrasound Facts
Patients have asked me these questions on a regular basis for years. Let’s get some ultrasound facts straight, shall we? I hope it’s helpful!
What’s the difference between ultrasound and sonogram?
Technically speaking, ultrasound is the study of the subject (the field of ultrasound) and a sonogram refers to the examination itself. Although we’re really not picky about what you call it.
Is ultrasound safe?
Biohazard testing over the past forty years reveals no ill effects of ultrasound on the fetus, mother, or sonographer. However, increasing levels of heat after scanning for several hours in one area can cause cavitation or the creation of bubbles. This is much longer than the time required for performing a diagnostic test. Since no one can predict the long-term effects, only the prudent and diagnostic use of the technology is recommended by ACOG, AIUM, and ACR. The benefits of the information from diagnostic exams for patient and physician currently outweigh any known risk.
Is Ultrasound radiation?
Ultrasound technology uses sound waves, NOT radio waves. I dedicate an entire post to just that subject in the link above. No radiation is emitted by ultrasound equipment or Dopplers utilized by your physician to detect Baby’s heartbeat. X-Ray emits radiation which is why, for example, your pregnant belly would be covered with a protective shield at your dentist’s office for X-Rays on your teeth.
Can my baby hear ultrasound?
Nope, Baby cannot hear the sound waves:) Ultrasound is just that…sound waves that operate at a frequency far beyond human hearing. Human hearing ranges from 20Hz to 20,000Hz. Diagnostic ultrasound operates in the millions of Hertz. Ultrasound probes range from about 2 – 13MHz.
True story ~ I became a little distressed once when a patient asked me if ultrasound sounded like a jet to a fetus. She had just read this in a pregnancy magazine in our waiting room! I reassured her this was inaccurate. This experience marked one of the many reasons I wanted to start my blog–to get reliable info to new moms like you!
What’s the difference between 2D, 3D, and 4D?
Almost everyone has seen the gray clouds of 2D ultrasound at one time or another. 2D allows us to see through organs and inside your baby.
Most people are familiar with 3D imaging as a fun way to see the outside of their baby. Additionally, the best and cutest 3D images are obtained later in the 2nd Trimester or early in the 3rd. Baby’s skin has developed more fat at this point which makes for chubbier cheeks! Occasionally, a high-risk practice (MFM or Maternal Fetal Medicine) will usually also use 3D to assist in visualizing a fetal abnormality. We also frequently use the technology for GYN scans to attempt a better look at uterine shape and/or IUD placement.
4D can be described as 3D in motion or a live 3D image. So, where 3D is a still image, a 3D video of Baby moving is actually 4D.
Ultrasound Credentials for Sonographers
What’s your title? Are you a nurse or in X-Ray?
We’re not nurses, though some of us do cross over from RT (X-Ray) or other areas of Radiology. Sonographer, Ultrasonographer, or Ultrasound Technologist are a few of our titles. We are specifically and formally educated in the field of Ultrasound.
RDMS stands for Registered Diagnostic Medical Sonographer. A sonographer earns these credentials through ARDMS when he or she has passed a registry examination in Ultrasound Physics as well as his/her ultrasound specialty. A certified sonographer typically has at least two years of experience under his/her belt.
DMS refers to someone who has completed some sort of formal or on-the-job ultrasound training but has not yet taken/passed the registry examination.
What do you think of those 3D places?
Having posted on this often, I understand a patient’s desire to go, but I’m not a fan. Not everyone who scans an expectant mom in a 3D non-medical business is a certified OB sonographer. Some have no formal ultrasound training whatsoever! I know you may be surprised by this little-known fact, and so was I.
These businesses are not regulated like medical practices. They may not be knowledgeable of or follow guidelines for equipment maintenance. Ultrasound equipment that is not properly maintained can be an electrical hazard for mother and/or fetus! Do your research and at least ensure your sonographer possesses RDMS or, at least, DMS credentials. Please read the post in the link above!
Performing Your Exam
When can I expect to have sonograms in my pregnancy?
Every practice is different. Most physician’s order a first-trimester ultrasound examination to date the pregnancy. This is usually performed with a transvaginal probe. If no other problems necessitate another scan, you’ll receive your next exam around 18-20 Weeks. Most women know this scan as the anatomy screen where we evaluate fetal and maternal parts for abnormalities.
*Your doc does not order this exam to determine fetal sex!* However, most sonographers will happily provide the info if at all possible (as long as policy allows)! Also, important to note here is that determining sex is never a guarantee nor should it be an expectation. Sometimes, those Little Sweet Peas just won’t cooperate! You can read more here about those limitations. Note of advice for moms: Don’t pre-plan your Gender Reveal party for the same day as your ultrasound! The health of your pregnancy determines whether you will receive more ultrasound scans later in your pregnancy.
Can you predict how much my baby will weigh at birth?
While we can measure your baby’s head, belly, and femur for an educated (called EFW or Estimated Fetal Weight) guess for weight at the time of your scan, a large discrepancy for weight determination exists due to fetal position and sonographer skill. We can typically track a trend for large or small babies. We know the average gained weight in the last few weeks is about 1/2 lb per week. However, every baby is different!
Ultrasound Facts About Fetal Sex
Most expectant moms today already know this little fact. The ultrasound machine is never “wrong” in determining fetal sex. Actually, it is the observer who is incorrect!
Guessing the wrong sex can be due to one or a combination of many factors. It is possible your baby was in a difficult position to see well. Maybe you were too early in your pregnancy for an accurate guess. In addition, an overall poor view can also limit fetal sex determination!
Facts About Your Results
Yes, the sonographer can read your examination. However, your OB/GYN physician or radiologist must ultimately interpret the images and report we create. Consequently, only your physician can legally give you results! Read more about why here.
However, most of us are more than happy to educate you about what you see on the monitor (minus a diagnosis!). I loved sharing how we measure and pointing out all your Baby’s parts for any inquisitive parents or family.
Feel free to email me at firstname.lastname@example.org with your comments or questions!
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