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  • Dr. Liz Homan

The Unknowns of Ultrasound

Updated: Dec 19, 2019

As always, I am not here to make your feel bad about any decision you have made or to judge you in anyway. I am here to inform you on a topic that I do not feel is often times discussed because I live by the quote “Do the best you can until you know better. Then when you know better, do better.”

So what is an ultrasound exam? According to the American Pregnancy Association, an ultrasound is a procedure that uses high-frequency sound waves to scan a woman’s abdomen to create a picture of the baby and placenta. Ultrasounds are used to detect or aid in the detection of abnormalities and conditions related to pregnancy. There are many reasons that ultrasounds are performed including estimating due date, confirming heartbeat, determining number of babies, finding out if baby is a girl or boy, and identifying baby and placenta position.

The way that an ultrasound works is that sound waves are moved through tissue and bounce back to provide the image. These sound waves can make thermal, vibrational or mechanical changes to the tissue it contacts.

The standard of care is for most women to receive two or more ultrasounds during their pregnancy, usually one in the first trimester to confirm heartbeat and then again in the second trimester for an anatomy scan. But did you know that the American Pregnancy Association states that “there is not a recommend number of ultrasounds that should be performed during routine prenatal care. Because ultrasound should only be used when medically indicated, many healthy pregnancies will not require an ultrasound.”

So let’s talk about a few of the unknowns.

  • Is ultrasound noisy? For us, no! But for the baby, they are not sure. One study found that the force from the impact of the ultrasound pulses produced an audible localized high-intensity noise due to the secondary vibrations in a woman’s uterus. When measured, the ultrasound produced 100 decibels of sound when pointed directly at the hydrophone. 20 decibels is a whisper, 110 decibels is the pain threshold for the average human and 150 decibels causes eardrum rupture. We so often see baby having their hands up over their face/ears during an ultrasound. Is that because it is so loud that they are covering their ears to protect themselves?

  • Does ultrasound make tissue hot? When the tissue vibrates it can cause the tissue to get hot and to also produce tiny bubbles (cavitation), which shift with the vibration. These tissue cells that are heated and vibrated are rapidly dividing to create your baby. Any thermal, vibrational or mechanical change to these cells may potentially cause a mutation. This mutation could lead to retardation or damage to fetal growth or it could result in the acceleration of cell division when it should not be accelerated.

  • Does ultrasound improve the health of my baby? No, not at all. The one thing it will do is detect an abnormality early enough for parents to choose to abort. But this detection is limited to only a few of the 5,000 potential chromosomal abnormalities. And the worst part is, ultrasound could misdiagnose abnormalities when there are none or detect abnormalities about which nothing can be done. This then results in the stress level of mom increasing, which negatively affect baby’s development.

If you are unsure of what to do, I encourage you to ask yourself “will the results of this scan alter the course of my pregnancy?” If the answer is no, then is it really necessary?

Another question to ask yourself is “will not knowing cause me more stress?” If you are a person who needs to know, then you need to know. Kyle and I had decided to not have ultrasounds with our pregnancy and to trust in my body. But that all changed when I fell down a few stairs, landing hard on my sacrum when I was 16 weeks pregnant with Jane. It was at the time when I was starting to feel her move but it was not consistent yet and then after the fall I was not feeling any movements. We decided that the stress that I was experiencing trying to feel baby move was more detrimental than a minute long ultrasound to hear the heart beat. As soon as I heard that beautiful sound, I could relax because I knew that my baby was healthy!

There are times when ultrasound is very beneficial but as the APA states, ultrasound is not needed in a healthy pregnancy!

And just as a reminder, I am in no way telling you what to do, or to make you feel bad about a decision that you have already made. I am here to inform you on a topic that I feel is important and often times just agreed on. This is why doing your research is so important!

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