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Autism’s Theoretical Causes, Ultrasound Scans: An Editorial

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In the previous article I talked about diet as a possible cause of autism. Now I will discuss ultrasound scans.

Sonograms were developed in the 1940s for war purposes, following earlier experiments into radar systems. The first medical ultrasonic systems appeared in the late 1940s, followed by the first use of obstetric ultrasound in 1958, when a report entitled "Investigation of abdominal masses by pulsed ultrasound" was published in the Lancet. (1 and 2)

Ultrasound scans are thought to be generally safe for the unborn baby because they use sound waves rather than radiation, but the FDA advise against "bonding" scans done for non-medical purposes, in case of unknown risk to the fetus. (3).

Ultrasound scans produce sound waves and heat that is capable of heating up body tissues. Many fetuses move away from the area where the probe has been placed and this may be because they are feeling heat.

Effect on Fetal Brain

A study in Epidemiology looked at Swedish men, one group who had been exposed to ultrasound during gestation and one group who were not, all born between 1973-1978. Of these, 6,858 men were born to mothers who had sonograms and a further 172,537 men whose mothers had not.

In the early 1970’s, sonograms were only given to women with high risk pregnancies and as the decade progressed, it began to be offered routinely to all pregnant women.

The researchers concluded:

"During the introduction phase (1973 to 1975) there was no difference in left-handedness between ultrasound exposed and unexposed (odds ratio = 1.03, 95% confidence interval (CI) = 0.91 to 1.17). When ultrasonography was offered more widely (1976 to 1978), the risk of left-handedness was higher among those exposed to ultrasound compared with those unexposed (odds ratio = 1.32, 95% CI = 1.16 to 1.51). We conclude that ultrasound exposure in fetal life increases the risk of left-handedness in men, suggesting that prenatal ultrasound affects the fetal brain."

Although being left-handed is not a problem, the study demonstrated how ultrasound can affect the brain of the developing baby. (4).

Fetal Response to Heat

Elevated body temperature in the fetus can cause heat shock response (HS response) , which is meant to assist the body’s recovery from the effects of heat and toxic agents.

Cell Stress Chaperones wrote:

"Maternal hyperthermia is a proven teratogen in all species studied. The HS response is inducible in early embryonic life but it fails to protect embryos against damage at certain stages of development. An embryo must absorb a threshold 'dose' of heat if defects are to be caused, the dose being the product of the level and the duration of elevation above the normal maternal temperature. The lowest elevation causing damage is 2-2.5 degrees C. Low elevations require longer durations and as the elevation increases, the time required is reduced logarithmically. Heat-induced defects are most common in the central nervous system (CNS) and include open neural tube, microencephaly, microphthalmia and neurogenic contractures. With activation of the HS response, normal protein synthesis is suspended (perhaps including those controlling induction of organs) and protective HS proteins are produced which rescue the embryo, but survival is achieved at the expense of normal development." (5)

So exposure to elevated temperatures during ultrasound may affect the normal development of the fetus.

A 1982 WHO report found that ultrasound was capable of causing behavioral developmental and immunological changes in animals. Examples include rats that were unable to clear injected colloidal carbon from their blood and a loss of erythrocyte surface antigens, changes to chromosomes, and lower birth weights. The rats also experienced post-natal behavioral changes and problems with bladder function. (6)

According to the FDA Consumer Magazine, the ultrasound machines we have now are stronger than the ones we had in the 1990s.

Danica Marinac-Dabic, M.D., an epidemiologist in the FDA's Office of Surveillance and Biometrics, said:

“Since ultrasound examinations in these studies took place in the late 1970s and early 1980s,and the fact that modern ultrasound equipment is capable of producing approximately eight times higher intensities than equipment used a decade ago, we continue to study the possible long-term effects of prenatal ultrasound in both animal and human epidemiologic studies." (3)

The same FDA article said speech delays are a possible effect of ultrasound scans. Some medical professionals, such as independent midwives, believe that the increase in intensity of sonograms and the rise in autism both occurred in the 1990s and could be linked. After all, it’s the first time in history that ultrasonic technology has been used on pregnant women on such a large scale.

Further research needs to be conducted on this theory.


1. A short History of the development of Ultrasound in Obstetrics and Gynecology, Ob-Ultrasound, Dr. Joseph Woo. Web. 12 September 2011. http://www.ob-ultrasound.net/history1.html

2. The Lancet, shown on Ob-Ultrasound, Dr. Joseph Woo. Web. 12 September 2011.

3. FDA Cautions Against Ultrasound 'Keepsake' Images, FDA Consumer Magazine (January-February 2004). Web. 12 September 2011. http://www.sdms.org/pdf/FDAKeepsake.pdf

4. Kieler H. et al. Sinistrality--a side-effect of prenatal sonography: a comparative study of young men, Epidemiology, 2001 Nov;12(6):618-23. Abstract:

5. Edwards MJ. Apoptosis, the heat shock response, hyperthermia, birth defects, disease and cancer. Where are the common links?, Cell Stress Chaperones, 1998 Dec;3(4):213-20. Abstract: http://www.ncbi.nlm.nih.gov/pubmed/9880233

6. International Program on Chemical Safety, Environmental Health Criteria 22, Ultrasound, Inchem (1982). Web. 12 September 2011. http://www.inchem.org/documents/ehc/ehc/ehc22.htm

Joanna is a freelance health writer for The Mother magazine and Suite 101 with a column on infertility, http://infertility.suite101.com/. She is author of the book, 'Breast Milk: A Natural Immunisation,' and co-author of an educational resource on disabled parenting.

She is a mother of five who practised drug-free home birth, delayed cord clamping, full term breast feeding, co-sleeping, home schooling and flexi schooling and is an advocate of raising children on organic food.

Reviewed September 26, 2011
by Michele Blacksberg RN
Edited by Jody Smith

Add a Comment5 Comments

Ultrasound is also used to break up gall stones and kidney stones. I know it is probably a higher frequency, but I still do not think prenatal ultrasound should be used routinely, only when a reason is presented. The fact that a doctor may have lousy palpatation skills or cannot use a fetascope to hear the fetal heart tones are not good reasons. Dr. Alice Stewart of Oxford University, UK advocated against prenatal X-rays and prenatal ultrasound. Ultrasound can cause heat by means of cavatation in the amniotic fluid, causing a fetal demise or birth defects. Women are told to avoid hot tubs for this reason, yet doctors subject them and their babies to this danger through ultrasound.

May 7, 2012 - 1:08pm
EmpowHER Guest

According to a 1917 study, you can remove ultrasounds from your body with baking soda. I read about it on empowher, which used to be a credible source of medical information.

September 28, 2011 - 3:09pm
(reply to Anonymous)

Really? Thanks for that! That's useful to know if I ever have anymore.

September 29, 2011 - 4:27am

The most recent review of the literature on ultrasound and health risks, conducted for the World Health Organization, concluded:

The electronic search identified 6716 citations, and 19 were identified from secondary sources. A total of 61 publications reporting data from 41 different studies were included: 16 controlled trials, 13 cohort and 12 case-control studies. Ultrasonography in pregnancy was not associated with adverse maternal or perinatal outcome, impaired physical or neurological development, increased risk for malignancy in childhood, subnormal intellectual performance or mental diseases. According to the available clinical trials, there was a weak association between exposure to ultrasonography and non-right handedness in boys (odds ratio 1.26; 95% CI, 1.03-1.54).
According to the available evidence, exposure to diagnostic ultrasonography during pregnancy appears to be safe." http://www.ncbi.nlm.nih.gov/pubmed/19291813

Yet another "theoretical cause of autism" that has no theoretical basis at all.

September 28, 2011 - 3:00pm
(reply to mike.stanton3)

As I said before, there are citations for and against most forms of medicine. The FDA has said there are unknown risks to scanning which is why they advise women not have have bonding scans. They would not advise that if there wasn't a theoretical issue. After all, getting to see your baby probably does improve bonding and is fun for the mother (usually if there isn't anything wrong).

I have no opinion myself on ultrasound as I think there needs to be more study. I had ultrasounds with my children (I had not read anything about them at the time). I did refuse the 12 week scan as I could not see a medical justification for doing one. They can't diagnose anything at that stage, it's just for dating which can be done by LMP. I also made the midwives use a pinard instead of an ultrasonic device to listen to the heartbeats, to avoid over-exposure.

I also had the 4D scan after reading that the waves weren't higher intensity, just fired in more directions. I have relatives with post-abortion syndrome and did it to give my son's pictures to a pro-life group. However, my son although healthy did not speak till he was nearly 3 years old (all he said was 'yeah' and 'mama') and now his speech is about 1 year behind his age so I decided to look into the scans more and that's when I found out there had been a concern about speech delays. My other 4 kids never had any 4D scanning during gestation and they were talking in sentences at 18 months old so I do wonder if there is an association.

September 29, 2011 - 4:22am
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We value and respect our HERWriters' experiences, but everyone is different. Many of our writers are speaking from personal experience, and what's worked for them may not work for you. Their articles are not a substitute for medical advice, although we hope you can gain knowledge from their insight.



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