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Ultrasound Safety ~ the research continues...
 Think before you scan...


Study Shows Potential Dangers of Ultrasound in Fetal Development

Aug. 24, 2006

Ultrasound: Weighing the Propaganda Against the Facts
by Beverly Lawrence Beech
Beverley A Lawrence Beech, honorary chair of the
Association for Improvements in the Maternity Services (AIMS),
is a freelance writer/lecturer and lives in the United Kingdom.

Ultrasound: More Harm than Good?
by Dr. Marsden Wagner
Marsden Wagner, MD is a neonatologist and perinatal epidemiologist.
He was responsible for maternal and child health in the European
Regional Office of the World Health Organization for fourteen years.

Questions About Prenatal Ultrasound and
the Alarming Increase in Autism
by Caroline Rodgers
Caroline Rodgers has 20 years experience as an editorin daily and
weekly journalism. She currently worksas a freelance writer,
specializing in writingfor nonprofit organizations.

FIRST, before you get an ultrasound -
Consider this...

Finally men everywhere might have a birth control option that won’t
rob them of the joys of living. Scientists at University of North Carolina
at Chapel Hill may have discovered a cheap, convenient and non-invasive method of male birth control: ultrasound.
The scientists believe that a single treatment can provide up
to six months of infertility that is reversible.

The team has received a $100,000 Grand Challenges Explorations
grant from the Bill & Melinda Gates foundation for their work. If the project pans out, this could have an incredible impact on global health. Ultrasound is low-cost, and is widely available in both developed and undeveloped nations. It should be noted that while this will theoretically prevent pregnancy, it will have no impact on the transmission of STIs.

Seminiferous tubule before (left) and after (right)
ultrasound treatment,

After nearly 50 years of use on pregnant women (with almost universal acceptance), there is still insufficient comprehensive research available that can truly evaluate the effects of ultrasound exposure on pregnancies and unborn babies.

       This makes it very difficult to draw reliable conclusions about the safety of diagnostic pregnancy ultrasounds or create clear guidelines for its responsible use. At this stage, most reports conclude that there are NO obvious adverse effects, BUT advise caution and the need for further research to confirm this.

 "Quiet Please!" says the fetus

Prenatal Ultrasound "sound levels"
in the uterus have been registered at
100-120 dB (decibel)
A 100-120 dB sound in air is similar to the
level of an approachingtrain !!
Human Pain Tolerance . . . 125 dB
Prenatal Ultrasound . . . 100 - 120 dB

Approaching train . . . 100 - 120 dB
Sandblasting . . . 115 dB
Riveting machine . . . 110 dB
Rock band . . . 108 - 114 dB
Boeing 707, 1 nautical mile before landing ...  106 dB

Jet flyover at 1000 feet . . . 103 dB

Bell J-2A helicopter at 100 ft . . . 100 dB

Boeing 737, 1  nautical mile before landing ... 97 dB

Power mower . . . 96 dB

Subway train at 200 ft . . . 95 dB

Motorcycle at 25 ft . . . 90 dB

Hearing Loss begins . . . 90 - 95 dB


Decibel (Loudness) Comparison Chart

Sound levels (dB) and relative loudness of typical noise sources


Extracorporeal shock wave lithotripsy(a.k.a. ultrasound) is used to DESTROY cells and to break down kidney stones.

"Extracorporeal shock wave lithotripsy (ESWL) is a common treatment for kidney stones that uses shock waves outside the body to break down the stones into smaller pieces that can more easily be eliminated. The shock waves pass through the skin to the stones. Doctors use an ultrasound device to locate the stones and direct the shocks."

Ultrasounic Cavitation is now being used in the medical aesthetics/weight loss field for body sculpting, that is
to destroy fat cells...

"The vibration of ion (positive and negative alternation of sound waves) produces a strong wave of pressure to fat cell membranes.
Usually a fat cell membrane cannot withstand this pressure, it will explode into the liquid content."
... SOoooo ...   IF ultrasound stops the ability of the male testicle
produce sperm, destroys kidney stones, and explodes fat cells...
We then must be COMPELLED to ask,

What is ultrasound doing to our unborn babies?

"The casual observer might be forgiven for wondering why the medical profession is
now involved in the wholesale examination of pregnant patients with machines
emanating vastly different powers of energy which is not proven to be harmless
to obtain information which is not proven to be of any clinical value by
operators who are not certified as competent to perform the operations..."

"If exposure to ultrasound… causes death of cells, then the practice of ultrasonic imaging at
16 to 18 weeks will cause loss of neurones [brain cells] with little prospect of replacement
of lost cells…The vulnerability is not for malformation but for maldevelopment leading to
mental impairment caused by overall reduction in the number of functioning
neurones in the future cerebral hemispheres."

Ultrasound Scans ~ Cause for Concern
Dr. Sarah Buckley

Ultrasound Safety

By Sarah Buckley, MD

Reproduced with permission from the newsletter of Sarah J Buckley, August 2009, and adapted from "Ultrasound: Scans: Cause for Concern" Chapter 5 in Gentle Birth, Gentle Mothering (2009).
See this chapter for full information and references.

For more about Sarah & to subscribe to her newsletter,

Ultrasound has been used to examine the unborn baby for more than forty years, but very little research has been done to determine possible short- or long-term effects on offspring.

Ultrasound is known to affect living tissues in several ways. Firstly, it causes heating in tissues while they are targeted by the sonar waves emitted by the transducer- the part of the machine that is placed on the pregnant woman's belly. Heating is especially likely later in pregnancy, when the baby's bones calcify: harder bones can reflect and concentrate heat more effectively. Researchers are especially concerned about heating effects on the growing (unborn or newborn) brain, which is especially vulnerable to heat, a known neurotoxin, because of proximity to the skull bones.(Barnett 2001)

The force of the ultrasound waves also causes the fluid within tissues to move, an effect known as "acoustic streaming". The velocity that is created can disrupt cell membranes and may explain observed effects such as increased stickiness in red cells following ultrasound exposure (Pohl, Rosenfeld et al. 1995), and the effects on brain cell migration mentioned below.

Ultrasound waves can also cause "cavitation", an effect that produces extreme temperatures and free radical formation in the small bubbles of air that exist in some mammalian tissues. This effect is significant for the newborn gut and lung, which are filled with air, but its significance for the unborn is not known. (Church and Miller 2007)

Studies of animals exposed to ultrasound in the womb have found effects including low birth weight;(Tarantal, Gargosky et al. 1995) low numbers of white (immune) blood cells in infancy;(Tarantal, Gargosky et al. 1995) damage to myelin nerve sheaths;(Ellisman, Palmer et al. 1987) brain hemorrhage;(Dalecki, Child et al.1999) and locomotor and learning difficulties in adulthood.(Suresh, Uma Devi et al. 2002)

A recent study in rats found abnormalities in neuronal migration (the process by which brain cells travel to the appropriate part of the brain during development) which correlated with duration of exposure to ultrasound in the womb. In this study, no rats with over 600 minutes total exposure to ultrasound during their 22 day gestation survived to 10 days.(Ang, Gluncic et al. 2006) Problems with neuronal migration have been linked with autism and dyslexia in humans

Human studies are very limited. Randomized trials from thirty years ago found no effects on learning, hearing or speech but found a higher risk of non-right-handedness associated with ultrasound exposure.(Salvesen, Bakketeig et al. 1992; Salvesen, Vatten et al. 1992; Salvesen, Jacobsen et al. 1993; Salvesen, Vatten et al. 1994) These findings have been replicated in other observational studies.(Kieler, Cnattingius et al. 2001; Kieler, Cnattingius et al. 2002) This effect implies that ultrasound can change the lateralization of the brain, which represents a a significant shift in brain development. Note that at the time of these studies, machine output was much lower, and examinations much shorter than today.

The only other large randomized trial with long-term follow-up involved offspring randomized to regular Doppler examination (see below) vs. standard ultrasound. Those exposed to Doppler were more likely to be born with low birth weight- the condition that Doppler was supposed to detect.(Newnham, Evans et al. 1993) Low birth weight has also been found in animal studies and may reflect interference with the growth hormone system. Comparing the two groups at age 8, researchers found no difference in learning or motor function,(Newnham, Doherty et al. 2004) but note that there was no unexposed ("control") group, so the true effects of ultrasound vs. no exposure cannot be determined from this study.

Two other randomized Doppler studies have also had concerning results. In one study, twice as many exposed babies died around the time of birth (Davies, Gallivan et al. 1992), and another found worse condition in labour and at birth (more fetal distress
and lower APGAR) among babies randomized to intensive Doppler examinations in pregnancy.(Newnham, O'Dea et al. 1991)

Doppler is used to measure flow in blood vessels and is also used, in low exposures, to detect and record the fetal heart, eg in hand-held machines and with fetal heart-rate monitoring. Doppler uses continuous waves, which give higher exposure than normal ultrasound, which uses pulsed waves.

This is very concerning because, in the last two decades, machines have become more sophisticated and output significantly higher. In 1993, the US FDA approved the sale of ultrasound machines with 8x higher output that previously allowed.

Exposure of unborn babies to these higher outputs has not been tested for long-or even short-term safety. Researchers note "There are no epidemiological [large population] prenatal ultrasound studies with commercially available ultrasound devices produced after 1990."(Salvesen 2007) This is despite increasing awareness by, for example, the American Institute of Ultrasound in Medicine, who stated in 2000 " ...the responsibility of an informed decision concerning possible adverse effects of ultrasound in comparison to desired information will probably become more important over the next few years."(Fowlkes and Holland 2000)

As authors of a large review of ultrasound safety in the prestigious US journal Epidemiology, 2002, concluded, "Until long-term effects can be evaluated across generations, caution should be exercised when using this modality during pregnancy."(Marinac-Dabic, Krulewitch et al. 2002)

Note that this information does not "prove" that ultrasound is unsafe, or that a single exposure during pregnancy will have long-term effects on your baby. Rather it raises concerns, and suggests that you need to consider the possible risks of ultrasound when making decisions about ultrasound for your baby.

You may also consider that the best medical evidence shows no benefit to mother or baby from a routine ultrasound in early pregnancy, apart from an increased number of terminations of pregnancy due to abnormalities detected on ultrasound. (Nelison 2000) (See my book for more about the accuracy of ultrasound in detecting abnormalities)

Ultrasound is a medical intervention that requires the same large body of high-quality research to establish safety,
short and long-term, as any other intervention involving the vulnerable unborn baby. At this time, it is impossible
to say whether the current use of prenatal ultrasound is safe or unsafe, because this research has not been done.

Selected references

Ang, E. S., Jr., V. Gluncic, et al. (2006). "Prenatal exposure to ultrasound waves impacts neuronal migration in mice." Proc Natl Acad Sci U S A 103(34): 12903-10.

Barnett, S. B. (2001). "Intracranial temperature elevation from diagnostic ultrasound." Ultrasound Med Biol 27(7): 883-8.

Church, C. C. and M. W. Miller (2007). "Quantification of risk from fetal exposure to diagnostic ultrasound." Prog Biophys Mol Biol 93(1-3): 331-53.

Dalecki, D., S. Z. Child, et al. (1999). "Hemorrhage in murine fetuses exposed to pulsed ultrasound." Ultrasound Med Biol 25(7): 1139-44.

Davies, J. A., S. Gallivan, et al. (1992). "Randomised controlled trial of Doppler ultrasound screening of placental perfusion during pregnancy." Lancet 340(8831): 1299-303.

Ellisman, M. H., D. E. Palmer, et al. (1987). "Diagnostic levels of ultrasound may disrupt myelination." Exp Neurol 98(1): 78-92.

Fowlkes, J. B. and C. K. Holland (2000). "Mechanical bioeffects from diagnostic ultrasound: AIUM consensus statements. American Institute of Ultrasound in Medicine." J Ultrasound Med 19(2): 69-72, p 70.

Kieler, H., S. Cnattingius, et al. (2001). "Sinistrality--a side-effect of prenatal sonography: a comparative study of young men." Epidemiology 12(6): 618-23.

Kieler, H., S. Cnattingius, et al. (2002). "First trimester ultrasound scans and left-handedness." Epidemiology 13(3): 370.

Marinac-Dabic, D., C. J. Krulewitch, et al. (2002). "The safety of prenatal ultrasound exposure in human studies." Epidemiology 13(3 Suppl): S19-22., p S19.

Neilson, J. P. (2000). "Ultrasound for fetal assessment in early pregnancy." Cochrane Database Syst Rev(2): CD000182.

Newnham, J. P., D. A. Doherty, et al. (2004). "Effects of repeated prenatal ultrasound examinations on childhood outcome up to 8 years of age: follow-up of a randomised controlled trial." Lancet 364(9450): 2038-44.

Newnham, J. P., S. F. Evans, et al. (1993). "Effects of frequent ultrasound during pregnancy: a randomised controlled trial." Lancet 342(8876): 887-91.

Newnham, J. P., M. R. O'Dea, et al. (1991). "Doppler flow velocity waveform analysis in high risk pregnancies: a randomized controlled trial." Br J Obstet Gynaecol 98(10): 956-63.

Pohl, E. E., E. H. Rosenfeld, et al. (1995). "Effects of ultrasound on agglutination and aggregation of human erythrocytes in vitro." Ultrasound Med Biol 21(5): 711-9.

Salvesen, K. A. (2007). "Epidemiological prenatal ultrasound studies." Prog Biophys Mol Biol 93(1-3): 295-300, p 301.

Salvesen, K. A., L. S. Bakketeig, et al. (1992). "Routine ultrasonography in utero and school performance at age 8-9 years." Lancet 339(8785): 85-9.

Salvesen, K. A., G. Jacobsen, et al. (1993). "Routine ultrasonography in utero and subsequent growth during childhood." Ultrasound Obstet Gynecol 3(1): 6-10.

Salvesen, K. A., L. J. Vatten, et al. (1994). "Routine ultrasonography in utero and speech development." Ultrasound Obstet Gynecol 4(2): 101-3.

Salvesen, K. A., L. J. Vatten, et al. (1992). "Routine ultrasonography in utero and subsequent vision and hearing at primary school age." Ultrasound Obstet Gynecol 2(4): 243-4, 245-7.

Suresh, R., P. Uma Devi, et al. (2002). "Long-term effects of diagnostic ultrasound during fetal period on postnatal development and adult behavior of mouse." Life Sci 71(3): 339-50.

Tarantal, A. F., S. E. Gargosky, et al. (1995). "Hematologic and growth-related effects of frequent prenatal ultrasound exposure in the long-tailed macaque (Macaca fascicularis)." Ultrasound Med Biol 21(8): 1073-81.

See Gentle Birth, Gentle Mothering chapter 5 for more information and full references.

More Ultrasound Safety Articles, Links & Resources:

ULTRASOUND - just looking CAN hurt!
Green Health Watch News

Dr. Ben Kim

Ultrasound Can Affect Fetal Brain Development
Dr. Ben Kim

Home Birth Midwifery Service
Cell: (832) 942-8324
Contact Kim