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.
Sources:
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.
http://www.ob-ultrasound.net/lancet.html
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:
http://www.ncbi.nlm.nih.gov/pubmed/11679787
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