There are moments in life when risks and benefits are clearly mapped out for most situations. There are also many moments when they are not. Having an ultrasound done is one of those moments. It isn’t like when you go to the grocery store and they have a small section labeled “natural” in every aisle. Have you noticed this? The rest of the aisle isn’t labeled. You don’t have to be a rocket scientist to to realize that the rest of the food is in fact "not natural." You do however need to be a sleuth to realize the hidden dangers of ultrasounds to your fetus.
If you have a child, you probably have a keepsake image much like the one above of Terra. We had the standard ultrasound done at 20 weeks, and one more at 36 weeks to confirm she was not breech. We also had a "keepsake video" ultrasound done, though. I didn't know that there was any risk to having one done, and the tech (that had no ultrasound training and simply rented an OB office in the evening) certainly didn't tell us. For future reference, you can find an FDA bulletin on the matter, here.
I am going to make a jump here and point out that several scientists are now trying to understand if there is a link between autism -a wide spectrum of disorders- and ultrasounds. If you type "ultrasounds" into a search engine, "and autism" comes up as a query.
Since the CDC released it's report stating that 1 in 88 children are now diagnosed with autism, a multitude of studies have been published pointing out that environmental and genetic factors alike contribute to the likeliness that a child will be diagnosed with autism. It is clear that there is not one aspect that the disorder can be blamed on, but instead a multitude of factors that work together.
That being said, is it possible that ultrasound is one of those factors? How does ultrasound affect the cells in the growing fetus and embryo? It does two things. It heats the highlighted area and creates cavitation (the forming and collapsing of gaseous bubbles). The effect this has on normal cell growth is under question. It has been shown that it can damage the myelin that covers the nerves. In mice, it has been shown to cause less cell division and more cell death. Effects on humans include pre-term labor or miscarriage, low birth-weight, poorer condition at birth, dyslexia, delayed speech development, and less right-handedness. Furthermore, the cell abnormalities caused by exposure to ultrasound can persist for several generations.
A 2006 study from the Proceedings of the National Academy of Science (PNAS) showed that mice exposed to ultrasound for 30 minutes or longer had "a small but statistically significant number of neurons fail to acquire their proper position and remain scattered within inappropriate cortical layers and/or in the subjacent white matter." Neurons develop in one part of the brain and move to the cerebral cortex after development, so if that movement is impacted, the development of the fetus could be compromised. The next year an editorial published in Obstetrics and Gynecology refuted the 2006 PNAS study stating that is unlikely for pregnant women to be exposed to ultrasound for seven hours. It is unlikely to have a seven hour ultrasound scan, but it is not at all unlikely to have continuous electronic fetal monitoring at the hospital once you are in labor. And labor can last a very long time-mine was 39 hours! Electronic fetal monitoring uses the same technology as ultrasound. There is one difference. An ultrasound scans intermittently while an electronic fetal monitor scans continuously. Therefore, an ultrasound wand is only on for 1/1000 of a second and an electronic fetal monitor is on continuously.
In a proposed rule from the Food and Drug Administration (FDA) in 1979, it was stated that “the possible risks associated with diagnostic ultrasound are not fully understood.” Furthermore, some of the “reported effects” of laboratory animals exposed to ultrasound in utero include “delayed neuromotor reflex development, altered emotional behavior, and fetal anomalies.” The proposed rule stated that the Commissioner believes “manufacturers should not state in advertising or promotional literature that diagnostic ultrasound is unequivocally safe.”
It is important to realize that correlation does not always equal causation, and just because someone has an ultrasound or two doesn't mean they will have a child with autism, but it is something to be aware of. Ultrasound machines today are eight times more powerful than those tested when first approved. More studies need to be done on the long-term risks of ultrasounds. In the meantime, if we have a second child, we will definitely be foregoing all ultrasounds unless demanded by the midwife for medical reasons (and believe me, it will drive me a little crazy not knowing the sex of the baby), but I am not trying to add an environmental risk factor into the mix just to satisfy my impatient nature. I will trust my body and my baby. Remember that you have the right to know all the risks of any medical procedure being done, and you have the responsibility to be an informed consumer. You should speak with your health-care provider about the risks and benefits of any procedure bring done.
More information on autism and ultrasounds:
From the FDA on ultrasounds
An ultrasound and autism website
Huffington Post article
Midwifery Today article
Studies about ultrasounds and autism:
A large ongoing study about autism from the CDC