Ultrasound: A collection of articles and links.
Conflicts of Interest: Understanding the Safety Issues Around Prenatal 3D Ultrasound
Ultrasound - weighing the propaganda against the facts
Ultrasound associated with mild brain damage ?
Weighing the Risks: What You Should Know about Ultrasound
Shadow of a doubt
excerpts about ultrasound from "What Doctors Don't Tell You"
Effect of diagnostic ultrasound during the fetal period on learning and
memory in mice
Neurotoxicity of diagnostic ultrasound in mice
Effect of prenatal ultrasound exposure on adult behavior in mice.[PubMed]
Unhindered-Living, The Dangers of Prenatal Ultrasound
1994 study by Wiley InterScience.
Conflicts of Interest: Understanding the Safety Issues Around Prenatal 3D Ultrasound
By Ted Nace
With Research Assistance from Merrian Fuller and Jonah Eaton
Posted June 2, 2005
the PDF of this article
Like many things, the safety of
ultrasound depends on the level of exposure. Studies of the lower exposures
common in the 1970s and 1980s are fairly reassuring. But since 1993,
allowable exposure levels have risen dramatically, and little research
has been done on the effects of these higher doses.
Meanwhile the use
of prenatal ultrasound continues to expand in what one consumer advocate
calls “the biggest uncontrolled experiment
in history.” (1) In 2000, approximately
2.7 million women in the United States received prenatal sonograms—some
67 percent of pregnant women. (2)
ultrasounds provide useful medical information, such as due date
or indications of malformations, most doctors consider the risks
After a medical ultrasound exam, parents typically take home a
simple 2D printout showing their fetus, and such pictures have become
virtual ritual of pregnancy in many industrialized countries.
manufacturers are pushing hard to win acceptance for a much more
extensive new ritual: a 4D (full motion 3D) movie of the unborn
provided by “fetal portrait” studios in shopping
malls. These movies are captured on DVD using state-of-the-art
equipment such as the Voluson 730 made by General Electric.
recent General Electric TV ad bypasses doctors to promote these
videos directly to parents, saying, “When you see your
baby for the first time on the new GE 4D ultrasound system,
it really is a miracle.” (3)
Who could resist?
General Electric’s website provides links to
commercial facilities where the new technology is available. With
names like “Womb
with a View” and “Peek-a-Boo,” these
businesses advertise heavily in parents’ magazines
and on the Internet, offering a variety of packages, ranging
basic 2D ultrasound
video ($75) to a deluxe package that includes a 20-minute
4D video set to music and stored on DVD, a set of wallet
a set of larger photographs suitable for framing ($285).
And the videos are in hot demand. Seeing their unborn baby
thrills and comforts many parents. Writes British doctor
Stuart Campbell, “Both
maternal and paternal reaction to the moving 3D image
is something we have not previously encountered. I have
fathers kiss the screen
or, more appropriately, their partner’s abdomen
in an ecstasy of recognition and pleasure.” (4)
The Safety Question
But what about safety? On their websites,
providers offer sweeping assurances that using ultrasound to
devoid of any risk. One confidently states, “Extensive
studies over 30 years have found that ultrasound
has not been shown to cause any harm
to mother or baby.” (5) Another
says flatly, “There
has never been a harmful effect shown by the use
of ultrasound. Many women
have multiple ultrasounds during pregnancy with no
negative effect on the baby.” (6) Yet
of studies have been conducted. Nothing has surfaced
yet that indicates any harmful
effects in the use of ultrasound on animals or on
even as business interests strive to reassure their
customers, government health officials and
In 1999, the American Institute
of Ultrasound in Medicine (AIUM) released the following statement:
The AIUM strongly discourages the non-medical
use of ultrasound for psychosocial or entertainment
purposes. The use of
(2D) or three-dimensional (3D) ultrasound to
the fetus, obtain a picture of the fetus, or
determine the fetal
without a medical
indication is inappropriate and contrary to responsible
medical practice. (8)
February 2004, the American Food and Drug Administration
(FDA) issued the following statement:
Persons who promote,
sell or lease ultrasound equipment for making “keepsake” fetal
videos should know that FDA views this as an
unapproved use of a medical device. In addition,
those who subject individuals to ultrasound
using a diagnostic ultrasound device (a prescription
device) without a physician’s order may
be in violation of state or local laws or regulations
of a prescription
Which is right,
the statements that fetal ultrasound is perfectly
safe or the cautions against it?
Why the concern
over a technology
has been in everyday use in doctors’ offices
How Ultrasound Impacts Fetal Tissue
Ultrasound is a form of energy—sound waves
vibrating at approximately a hundred times the frequency of normal
the waves can affect tissue in a variety
of ways. Heat is one effect. In
although ultrasound itself does not produce
audible noise, secondary vibrations can
as loud as 100 decibels, causing
fetuses to move. (10) Other
effects, still poorly understood, include
bubbles in tissue (a process known as
cavitation), sheering forces within tissues,
flows within fluids, and creation of minute
quantities of toxic chemicals. (11)
restrictions preclude the direct study
of ultrasound effects on humans.
are using animal studies as well as data
from populations of humans exposed to ultrasound in the past.
to one 1998 study, temperature increases of 4.5 degrees Centigrade
Fahrenheit) were measured
brain of late-gestation live guinea-pig
fetuses insonated in utero for 2
minutes by pulsed Doppler-type
ultrasound. (12) Other
guinea-pig studies have shown adverse
cell division in bone marrow following
In October 2004, Pasko Rakic, Chairman of the Neurobiology Department
at Yale University, announced that he and his colleagues had observed
disruption of normal migration of cells in the brains of fetal mice
following exposure to ultrasound. Rakic is now conducting a $3 million
study to see if the same effects occur in the offspring of rhesus macaque
monkeys scanned during pregnancy. In humans, such disruption is known
to be caused by certain viruses, mutations, and drugs, and it is linked
to a range of disorders including autism and learning disabilities. 
2001, a team of Polish researchers published
actual temperature readings
an adult human
brain during ultrasound
exposure. The results showed no temperature
increase, causing the researchers
to hypothesize that the human brain enjoys
better cooling capacities than the brains
mammals. (15) But
no one knows
whether the rapidly developing brain
of the human fetus is similarly protected
from ultrasound-induced heat. To determine
whether such heating may produce subtle
in human populations,
sought to compare the health histories
of children exposed to ultrasound and
the same data for children not exposed.(16)
To date, studies of humans exposed to
ultrasound have shown the following possible
speech development. (17) But
only one effect, a higher rate of left-handedness
boys exposed to neonatal
been observed in at
least three separate studies.
Why Worry about Left-handed Boys?
If the only
demonstrated result of neonatal ultrasound is more left-handed boys,
why be concerned? The
answer is twofold.
is statistically linked to many cognitive
and developmental problems ranging
difficulties to autism
Second, many researchers view
a rising rate of left-handedness as the neurological
a “canary in a coal mine,” a
suggestion that other types of minor
brain damage may also arise. According
reporter Robert Matthews, the increase
left-handedness associated with neonatal
could be the result of subtle
brain damage causing people who ought
genetically to be right-handed to
become left-handed. (18)
left-handedness findings were based
on health data from children
the late 1970s
and early 1980s. But by the mid-1990s,
average exposure levels had risen
significantly. In 2003, the ECMUS
Safety Committee noted that time-averaged
values of intensity
in the most common
scanning mode, “are
now up to 1000 times greater than
those reported in the 1970s.” (19) Scientists
need to repeat the left-handedness
studies, as well as studies of other
possible effects, on this younger,
more intensively exposed
population. To date, such follow-up
studies have not been done. (20) Thus,
claims that “there has
never been a harmful effect shown” simply
do not apply to today’s ultrasound
FDA Reduces Oversight While Increasing Risk Levels
A milestone came
in 1993 when the FDA raised the maximum output of
used in obstetrics
up to 720
milliwatts per square centimeter.
(21) The FDA was persuaded
that operators needed greater flexibility,
when confronting life-and-death
situations such as determining
blood flows in tiny
coronary arteries in the midst
ongoing heart attack.
At the time
it raised the exposure ceiling, the FDA began requiring
manufacturers to add two
on-screen safety indexes.
the heating of bone or tissue;
the other “mechanical” effects,
including cavitation caused by
the expansion of gas bubbles,
sheering forces within
flows within fluids.
expected that a well trained
sonographer using the
safety indexes properly
would not subject patioents
levels of ultrasound exposure
than under the previous system
But then the FDA failed to ensure
that sonographers are properly
of sonographer training
is dismally inadequate. Dr. Jacques
Abramowicz, Professor of Obstetrics
and Radiation at the
Chicago, said, “Only
two to three percent of the population
doing ultrasound really know
what the thermal index
and the mechanical
operators are confused by the
complexity of interactions
between sound waves and human
ways different ultrasound
modes affect exposure, and the
different responses caused in
the body. Bones
muscles, for example.
And bone is extremely sensitive
to ultrasound heating: the skull
fetus heats up 50
time more quickly
when exposed to ultrasound. (22) This
means that brain structures lying
as the pituitary
and the hypothalamus,
especially at risk of secondary
Yet another wild
card is the difference in sensitivity
and adult tissue: fetal
brain tissues are more
disturbance because of the developmental
changes taking place.
The on-screen temperature
safety indexes can give false assurance,
According to Dr.
Abramowicz, the actual amount
of tissue heating may exceed
by the safety index by a factor
of 2 to 6. Thus, actual heating
reach a dangerous
when the safety
cannot agree where to set the “safety baseline” for
temperature effects. Most
researchers regard a temperature rise of .5 degrees Centigrade to
be safe. But
according to John Abbott, PhD,
director of standards communication
for Philips Medical Systems, the indexes “cannot be considered
as absolute measures of anything.They
apply to the machine,
and operating condition in
use at the time. A thermal
index of 4 is more than a thermal index
Acceptable Levels of Risk
the uncertainties, doctors continue to use medical
diagnostic benefits are
believed to outweigh any
potential harm. Says Dr.
common rationale is that
has been in use for 45
years now and we haven’t
had missing arms and legs.”
other words, doctors accept
that there may be
but they believe
beneficial practice when
performed by a trained
operator for diagnostic
purposes. According to
Joshua Copel, Professor
of Obstetrics and Gynecology
at Yale University, “It’s
impossible to prove ultrasound
is completely safe, but
if you’re getting
medically helpful information,
then the tradeoff
for keepsake fetal portraits,
Dr. Copel advises his patients
clear: “We don’t
know what equipment they’re
using, what the acoustic
output is, and what the
training of the personnel
heat increases over the
length of exposure,
of any medical
But in multiple investigations
of keepsake fetal portrait
studios, FDA investigators
to higher machine
settings for as long as
an hour in
order to obtain fetal pictures,
than is considered prudent. (24)
What Protection from the FDA?
Despite the FDA’s own findings and expressed concerns, the federal
government has recently
adopted a notably softer stance toward the practice of “keepsake” fetal
ultrasound. When keepsake portrait studios first appeared in the 1990s,
the FDA cracked down-—hard.
In 1994, the agency issued
warnings against seven
companies to stop making
or face seizure,
or other regulatory
By May 1995, five of
had shut down. (25)
late as 1999, the FDA
continued to issue
as the following
Ultrasound of Coral
Springs, Florida: “…to
use the UM4A Ultrasound
System for non-diagnostic
video taping sessions
of the fetus for keepsake
videography … is
in violation of the law.”
although fetal portrait
studios are rapidly proliferating,
agency has stopped
any warning letters.
In response to queries,
FDA press officer Sharon
Snider said, “We’re
considering what our
to “The Gray Sheet,” a
medical devices trade
publication, the FDA
changed course after
the arrival of Bush-appointee
Dan Troy as chief legal
counsel. (26) Prior
to joining the FDA, Troy
and tobacco companies
on legal cases against
the FDA. (27) At
the FDA, Troy issued
policy requiring all
warning letters to drug
companies and medical
to be approved
by his office. In the
wake of the new policy,
the number of warning
letters issued by the
agency dropped by 70
percent. (28) In
November, 2004, Troy
left the FDA
after being widely criticized
for intervening on behalf
of drug companies, including
his former client Pfizer,
to date there is no indication
that his departure has
resulted in any shift
toward more active enforcement
of the FDA’s
policy on keepsake fetal
Under a passive
FDA, the ultrasound industry
the official ban on
of ultrasound equipment,
most keepsake fetal portrait
studios routinely advertise
there is money to be made at all levels
$3.2 billion in 2004
according to one trade
that figure does
not include the incomes
of franchisers such
Keepsake, or mom-and-pop
projected to triple
by 2009. (30) Market
researcher Harvey Klein recently noted
that for General Electric
4D technology has been
growth, helping that
company achieve an
sales in 2003, three
growth for other manufacturers.
Social Agendas Complicate the Safety Discussion
The biggest wildcard
in the politics of
ultrasound — even
bigger than big money— is
embrace of the technology.
Calling the images
a “miracle,” activist
newsletters and magazines
abound in reports
of women who change
3D videos of their
Consent Act,” which
would subsidize ultrasound
equipment for anti-abortion “crisis
pregnancy counseling” centers.
If passed, the law
would provide up
to 50 percent
of the cost of ultrasound
centers, and would
also require that
women be shown images
of their unborn fetus.
Has abortion politics
played a role in
the FDA’s shift
toward a passive
Neither FDA officials
nor business leaders
are willing to answer
the question on the
the record, I don’t
doubt it for a minute,” said
We've Seen This Before
Some observers compare
the fetal portrait
fad to earlier
and the natural
desire to look
inside the human
in the 1920s,
a device known
as the “shoe-fitting
a common feature
in shoe stores,
images of customers’ feet.
of warnings by
attempts by regulatory
agencies to stop
until the early
A Gap in the Safety Net
At the center of the fetal
portrait fad are the simple, normal desires of expectant parents
to be reassured about the health and well being
of their new baby. Sadly, that very desire for reassurance and
enjoyment makes parents vulnerable to sales pitches for technologies
safety remains uncertain. Ultrasound, of course, plays a vital
role when needed for a legitimate medical purpose. But as with any
technology, caution is advised. Says Dr. Abramowicz: “I recommend
against keepsake ultrasounds. The principle is simple. You should
not use a medical device for a non-medical purpose.”
the issue of prenatal ultrasound has highlighted a serious gap
in the regulatory system. Unlike new drugs, medical devices are
not subjected to rigorous animal and human testing prior to being
released. While it is reassuring that researchers are finally
beginning to understand
just how ultrasound may affect brain development, the best time
for such research would have been before the FDA loosened the ceilings
on ultrasound exposure. Since 1993, when the rules were changed,
some 28 million pregnant women have been exposed to ultrasound.
citizens should push for full enforcement of the FDA’s
existing rules on ultrasound, so that prenatal ultrasound is limited
to appropriate medical uses. But action needs to go further than
that. The approval process needs to be changed so that medical devices,
the new higher intensity ultrasound machines, are fully tested
before – not
after – being put into widespread use.
Notes and Links
1. 1993 statement attributed to UK consumer activist Beverly Beech
in Sarah Buckley, “Ultrasound Scans: Cause for Concern,” Nexus,
Vol. 9, No. 6, Oct.-Nov. 2002.
2. Figures are for the year 2000. Source: National Center of Health
Statistics of the Centers for Disease Control and Prevention, “Live
births to mothers with selected obstetric procedures,” National
Vital Statistics Reports, Vol. 50, No. 5, Feb. 12, 2002, Table 36.
4. Stuart Campbell, “4D, or not 4D: that is the question,” Ultrasound
in Obstetrics and Gynecology, Vol. 19, No. 1, Dec. 12, 2002, 1-4.
9. Carol Rados, “FDA cautions against ultrasound ‘keepsake’ images,” FDA
Consumer, Jan.-Feb., 2004. at www.fda.gov/fdac/features/2004/104_images.html
10. Eugenie Samuel, “Fetuses can hear ultrasound examinations,” New
Scientist, Vol. 10, No. 4, Dec. 4, 2001. Mostafa Fatemi, Paul L. Ogburn,
Jr., James F. Greenleaf, “Fetal Stimulation by Pulsed Diagnostic
Ultrasound,” Journal of Ultrasound in Medicine, Vol. 20, 2001,
11. S.B. Barnett, “Can diagnostic ultrasound heat tissue and
cause biological effects?” In S.B. Barnett and G. Kossoff, eds.,
Safety of Diagnostic Ultrasound (Carnforth, UK: Parthenon Publishing,
12. M.M. Horder, S.B. Barnett, G.J. Vella, M.J. Edwards, A.K.W. Wood, “Ultrasound-induced
temperature increase in the guinea pig fetal brain in utero: third-trimester
gestation.” Ultrasound in Medicine and Biology, Vol. 24, No.
5, June 1998, 1501-10; M.M. Horder, S.B. Barnett, G.J. Vella, M.J.
Edwards, A.K.W. Wood, “In vivo heating of the guinea pig fetal
brain by pulsed ultrasound and estimates of Thermal Index,” Ultrasound
in Medicine and Biology, Vol. 24, No. 5, June 1998, 1467-74.
13. S.B. Barnett, M.J. Edwards, P. Martin, “Pulsed ultrasound
induces temperature elevation and nuclear abnormalities in bone marrow
cells of guinea pig femurs.” Proceedings of the 6th World Congress
on Ultrasound Medicine, No. 3405 (Copenhagen, Denmark: WFUMB, 1991).
14. Jim Giles, “Ultrasound scans
accused of disrupting brain development,” firstname.lastname@example.org, 10/27/2004
15. Z. Mariak, J. Krejza, M. Swiercz, T. Lyson,
J. Lewko, “Human
brain temperature in vivo: lack of heating during transcranial color
Doppler US,” Journal of Neuroimaging, Vol. 11, No. 3, 2001, 308-312.
16. D. Marinac-Dabic, C.J. Krulewitch, and R.M.
Moore, Jr., “The
safety of prenatal ultrasound exposure in human subjects.” Epidemiology,
May 13, 2002 (2 Supplement): S19-22.
17. K.A. Salvesen, L.J. Vatten, S.H. Eik-Nes,
K. Hugdahl, L.S. Bakketeig, “Routine
ultrasonography in utero and subsequent handedness and neurological
development,” British Medical Journal, Vol. 307, 1993, 159-64.
H. Kieler, O. Axelsson, B. Haglund, S. Nilsson, K.A. Salvesen, “Routine
ultrasound screening in pregnancy and children’s subsequent handedness.” Early
Human Development, Vol. 50, 1998, 233-45.
18. Robert Matthews, “Ultrasound Scans
Linked to Brain Damage in Babies,” Epidemiology, Vol. 12, Dec.
19. ECMUS Safety Committee, “Diagnostic
Ultrasound Exposure,” EFSMB
Newsletter, Jan. 2003.
20. Carol Rados, “FDA cautions against
ultrasound ‘keepsake’ images,” FDA
Consumer, Jan.-Feb., 2004.
21. Carol Rados, “FDA cautions against ultrasound ‘keepsake’ images,” FDA
Consumer, Jan.-Feb., 2004.
22. S.B. Barnett, “Can diagnostic ultrasound
heat tissue and cause biological effects?” In S.B. Barnett and
G. Kossoff, eds., Safety of Diagnostic Ultrasound (Carnforth, UK: Parthenon
23. S.B. Barnett, “Sensitivity to diagnostic
ultrasound in obstetrics,” In
S.B. Barnett and G. Kossoff, eds., Safety of Diagnostic Ultrasound.
(Carnforth, UK: Parthenon Publishing, 1998), 58.
24. Carol Rados, “FDA cautions against
ultrasound ‘keepsake’ images,” FDA
Consumer, Jan.-Feb. 2004.
25. Marian Segal, “FDA Says No to ‘Premature’ Videos,” FDA
Consumer, Sept. 1995.
26. “‘Keepsake’ Fetal Ultrasounds
Persist Despite FDA’s Dim View of Practice,” The Gray Sheet,
June 2, 2003.
27. Michael Kranish, “FDA Counsel’s
Rise Embodies US Shift,” Boston
Globe, Dec. 22, 2002.
28. James G. Dickinson, “FDA Cuts Warning
Letters by 70%,” Washington
29. National Electrical Manufacturers Association
30. According to market researcher Frost and
Sullivan, 3D ultrasound equipment sales are projected to triple from
$147.1 million in 2002
to $517.5 million in 2009. Source: “3D medical imaging will expand
in U.S. market,” Medical Imaging, Mar. 2003, at www.medicalimagingmag.com/news/2003-03.asp
31. “GE Healthcare takes the global leadership
20, 2004, at www.4d-ultrasounds.com/ultrasounds/ge-position.htm
32. Jacalyn Duffin and Charles R. R. Hayter, “Baring
the Sole: The Rise and Fall of the Shoe-Fitting Fluoroscope,” Isis,
Vol. 91, No 2, June 2000, 260-282. A brief history of the shoe-fitting
can also be found in the Oak Ridge Associated Universities Health Physics
Historical Instrumentation Collection at www.orau.org/ptp/collection/shoefittingfluor/shoe/htm
A collection of articles and links.
From: "Sheri Nakken" [See bottom of page]
Sent: Tuesday, December 21, 2004 3:41 AM
Subject: Ultrasound Unsound? (Collection of info)
OK to share........
Here is a link to an interesting article entitled Ultrasound -
weighing the propaganda against the facts. It was written by the
author of Ultrasound Unsound?
I have seen other studies identifying negative side effects of
ultrasounds. One in particular found that as little as 1 ultrasound
could delay a child's speech by as much as 9 months. This study was
done in Canada, not the US. Other findings have suggested that the
increase in left-handedness among children who were scanned before
birth is linked to the ultrasound, which would show that the scan
does alter the brain in some way.
In the US, keep in mind that medical equipment does not undergo the
type of testing that a drug must go through to get on the market.
The scans used today are more invasive than the earlier ones, so it
will take a few more decades to really know the outcome. The recent
generations of children who have been scanned are in fact the guinea
pigs that will decide the safety of ultrasounds -- which have done
nothing to lower childbirth death rates, but have sent the C-section
rate dangerously high in the US.
The article above points out that the doppler, used to detect heart
tones on every prenatal visit unless you have a midwife (who uses a
fetalscope), may cause even more damage than the ultrasound.
This is straight from the journal "Epidemiology" (Dec 2001), and
suggests that ultrasound is associated with mild brain damage.
My boss, Dr. Mark Ellisman, is a world-renowned research scientist at UCSD
who specializes in imaging technologies for the study of brain structure
at the cellular level; he has personally found evidence of something
called "cavitation", which is the "rapid formation and collapse of vapor
pockets" in fluid within tissue. When my wife and I became pregnant
he warned me to keep the ultrasound as short as possible. He knows what
he's talking about.
Here's a relevant quote:
"Free radical production in amniotic fluid and blood plasma by medical
ultrasound, probably following gaseous cavitation, has been detected
by Crum et al (1987). This provides a likely mechanism for the
origin of the DNA damage. Because of these confirmations and a report
by Ellisman et al (1987) that diagnostic levels of ultrasound may disrupt
myelination in neonatal rats, the need for regulation, guidance, and
properly controlled clinical studies is clear."
Here's another useful link:
So please don't consider this a benign procedure or an opportunity
to get some pretty pictures. and *please* don't get an extra
3D ultrasound, which is a very long scan, to get the 3D picture
of your baby. There is a real risk, and it's just not worth it.
Do a Google search on "+ultrasound +cavitation" or "+ultrasound +Ellisman"
and convince yourself.
Just my .02
Weighing the Risks: What You Should Know about Ultrasound
By Sarah Buckley
Issue 102, September/October 2000
Ultrasonography was originally developed during World War II to detect
enemy submarines. Its use in medicine was pioneered in Glasgow, Scotland,
by Dr. Ian Donald, who first used ultrasound to look at abdominal tumors,
and later babies in utero in the mid-1950s.1 The use of ultrasound in
pregnancy spread quickly.
In westernized healthcare systems, ultrasound, which may be offered to a
pregnant woman either to investigate a possible problem at any stage of
pregnancy or as a routine scan at around 18 weeks, has become almost
universal in pregnancy. In Australia, where I live, 99 percent of pregnant
women have at least one scan, paid for in part by our federal government,
through Medicare. In fact, from 1997 to 1998 Medicare paid out AU$39
million for obstetric scans, compared to AU$54 million for all other
obstetric Medicare costs. In the US, the American College of Obstetrics and
Gynecology (ACOG) estimates that 60 to 70 percent of pregnant women are
scanned, despite an official statement from ACOG that recommends against
routine ultrasound.2 At a cost of roughly $300 per procedure, this
represents a cost of approximately $70 to $80 million each year in the US.
Besides routine scans, ultrasound can be prescribed to investigate problems
such as bleeding in early pregnancy. Later in pregnancy, ultrasound can be
used when a baby is not growing, or when breech or twin births are
suspected. In such cases, the information gained from ultrasound can be
very useful in decision-making, and generally most professionals support
the use of ultrasound in this context.
It is such use of routine prenatal ultrasound (RPU) that is more
controversial, as this practice involves scanning all pregnant women in the
hope of improving the outcome for some mothers and babies. RPU seeks to
gain four main types of information:
Estimated due date. Dating a pregnancy is most accurate at early stages,
when babies vary the least in size. By contrast, at 18 to 20 weeks the
expected date of delivery is only accurate to within a week either way.
Some studies have suggested, however, that an early examination or a
woman's own estimation of her due date can be as accurate as RPU.3,4
Unsuspected physical abnormalities. While many women are reassured by a
normal scan, in fact RPU detects only between 17 percent and 85 percent of
the one in 50 babies that have major abnormalities at birth.5,6 A recent
study from Brisbane, Australia, showed that ultrasound at a major women's
hospital missed about 40 percent of abnormalities, many of which are
difficult or impossible to detect.7 The major causes of intellectual
disability, such as cerebral palsy and Down syndrome, or heart and kidney
abnormalities, are unlikely to be picked up on a routine scan.
There is also a small chance that the diagnosis of an abnormality is false
positive. In some instances, normal babies have been aborted because of
false-positive diagnoses.8 A United Kingdom survey found that one in 200
babies aborted for major abnormalities were wrongly diagnosed.9
In addition to false positives, there are also uncertain cases in which the
ultrasound image cannot be easily interpreted, and the outcome for the baby
is not known. In one study involving babies at higher risk of
abnormalities, almost 10 percent of scans were uncertain.10 This can create
immense anxiety for the woman and her family that may not be allayed by the
birth of a normal baby: in the same study, mothers with questionable
diagnoses still had associated anxiety three months after the child's
birth. Uncertain findings also lead to repeated and/or prolonged scans,
increasing the expense, inconvenience, and dosage of ultrasound.
In some cases of uncertainty, further tests such as amniocentesis are
recommended. In such situations, there may be up to two weeks wait for
results, during which time a mother must consider whether or not she will
terminate the pregnancy if an abnormality is found. Even mothers who
receive reassuring news have felt that this process has interfered with
their relationship with their babies.11
Location of the placenta. A very low-lying placenta (placenta previa) puts
mother and baby at risk of severe bleeding, and usually necessitates a
cesarean section. However, 19 out of 20 women who have placenta previa
detected on RPU will be needlessly worried, as the placenta will
effectively move upwards as the pregnancy progresses.12 Furthermore,
detection of placenta previa by RPU has not been found to be safer than
detection in labor.13
Multiple fetuses. Ultrasound can detect the presence of more than one baby
at an early stage of pregnancy, but this knowledge affords no documented
health advantages for mother or babies, and, without RPU, almost all
multiple pregnancies are discovered before birth.14
Why Are RPUs So Popular?
Supporters of RPU argue that availability of ultrasonic information leads
to better outcomes for mother and baby. While this seems logical,
researchers have not found evidence of significant benefit from RPU, and
the issue of the safety of ultrasound has not yet been resolved.
From a research perspective, the most significant benefit of RPU is a small
reduction in perinatal mortality, that is the number of babies dying around
the time of birth. This is, however, merely a statistical reduction since
perinatal mortality rates do not include deaths that occur before five to
six months' gestation. Often when a baby is found to have a fatal
abnormality on RPU, the pregnancy is terminated before this time, excluding
the baby from perinatal statistics.
RPU proponents presume that early diagnosis and termination is beneficial
to women and their families. However, the discovery of a major abnormality
on RPU can lead to very difficult decision-making. Some women who agree to
have an ultrasound are unaware that they may get information about their
baby that they do not want, as they would not contemplate a termination.
Other women can feel pressured to have a termination, or at least feel some
emotional distancing from their "abnormal" baby.15
Furthermore, there is no evidence that women who have chosen termination
are, in the long term, psychologically better off than women whose babies
have died at birth. In fact, there are suggestions that the reverse may be
true in some cases.16 In choosing a possible stillbirth over a termination,
women at least get social acknowledgment and support, and are able to
grieve openly. Where termination has been chosen, women are unlikely to
share their story with others and can experience considerable guilt and
pain from the knowledge that they themselves chose the loss.17
Another purported benefit of RPU is a reduced risk of being induced for
being "overdue," because RPU dating gives a more certain estimated due
date. However, there is no clear evidence that this is true, as the
possibility of induction is more determined by hospital or doctor policy
than by the availability of RPU.19
Many supporters of RPU claim that it's a pleasurable experience, and
contributes to bonding between mother (and father, if he is present) and
baby. While it is true that it can be exciting to get a first glimpse of
one's baby in utero, there is no evidence that it helps attachment or
encourages healthier behavior toward the baby.20 For most women, bonding
occurs naturally when they begin to feel fetal movements at 16 to 20 weeks.
Reasons for Concern
Ultrasound waves are known to affect living tissues in at least two ways.
First, the sonar beam heats the highlighted area by about 1°C (2°F). This
is presumed to be insignificant, based on whole-body heating in pregnancy,
which seems to be safe up to 2.5°C (5°F).21 The second effect is
cavitation, where the small pockets of gas that exist within mammalian
tissue vibrate and then collapse. In this situation "...temperatures of
many thousands of degrees Celsius in the gas create a wide range of
chemical products, some of which are potentially toxic."22 The significance
of cavitation in human tissue is unknown.
A number of studies have suggested that these effects are of real concern
in living tissues. The first study indicating problems analyzed cells grown
in the lab. Cell abnormalities caused by exposure to ultrasound were seen
to persist for several generations.23 Another study showed that, in newborn
rats (who are at a similar stage of brain development as humans at four to
five months in utero), ultrasound can damage the myelin that covers
nerves,24 indicating that the nervous system may be particularly
susceptible to damage from this technology. In 1999, an animal study by
Brennan and colleagues, reported in New Scientist,25 showed that exposing
mice to dosages typical of obstetric ultrasound caused a 22 percent
reduction in the rate of cell division, and a doubling of the rate of cell
death in the cells of the small intestine.
Studies on humans exposed to ultrasound have shown possible adverse
effects, including premature ovulation,26 preterm labor or miscarriage,27,
28 low birthweight,29 poorer condition at birth,30, 31 dyslexia,32 delayed
speech development,33 and less right-handedness,34, 35 a factor which in
some circumstances can be a marker of damage to the developing brain. In
addition, one Australian study showed that babies exposed to five or more
ultrasounds were 30 percent more likely to develop intrauterine growth
retardation (IUGR)--a condition that ultrasound is often used to detect.36
Two long-term randomized controlled trials, comparing exposed and unexposed
children's development at eight to nine years of age, found no measurable
effect from ultrasound.37, 38 However, as the authors note, intensities
used today are many times higher than in 1979 to 1981. A later report of
one of these trials39 indicated that scanning time was only three minutes.
More studies are obviously needed in this area, particularly in Doppler
ultrasound, where exposure levels are much higher, and in vaginal
ultrasound, where there is less tissue shielding the baby from the
A further problem with studying ultrasound's effect is the huge range of
output, or dose, possible from a single machine. Modern machines can give
comparable ultrasound pictures using either a lower or a 5,000 times higher
dose,40 and there are no standards to ensure that the lowest dose is used.
Because of the complexity of machines, it is difficult to even quantify the
dose given in each examination.41 In the US, as in Australia, training is
voluntary (even for obstetricians), and the skill and experience of
operators varies widely.
In all the research done on ultrasound, there has been very little interest
in women's opinions of RPU, and the consequences of universal scanning for
women's experience of pregnancy. In her thoughtful book on prenatal
diagnosis, The Tentative Pregnancy,42 Barbara Katz Rothman suggests that
the large numbers of screening tests currently being offered to check for
abnormalities makes every pregnancy tentative until reassuring results come
Ultrasound is not compulsory, and I suggest that each woman consider the
risks, benefits, and implications of scanning for her own particular
situation. If you decide to have a scan, be clear about the information
that you do and do not want to be told. Have your scan done by an operator
with a high level of skill and experience (usually this means performing at
least 750 scans per year) and say that you want the shortest scan possible.
If an abnormality is found, ask for counseling and a second opinion as soon
as practical. And remember, it's your baby and your choice.
1. Ann Oakley, "The History of Ultrasonography in Obstetrics," Birth 13,
no. 1 (1986): 8-13.
2. American College of Obstetricians and Gynecologists, "Routine Ultrasound
in Low-Risk Pregnancy, ACOG Practice Patterns: Evidence-Based Guidelines
for Clinical Issues," Obstetrics and Gynecology 5 (August 1997).
3. O. Olsen et al., "Routine Ultrasound Dating Has Not Been Shown to Be
More Accurate Than the Calendar Method," Br J Obstet Gynaecol 104, no. 11
4. H. Kieler, O. Axelsson, S. Nilsson, and U. Waldenstrom, "Comparison of
Ultrasonic Measurement of Biparietal Diameter and Last Menstrual Period as
a Predictor of Day of Delivery in Women with Regular 28-Day Cycles,"
Acta-Obstet-Gynecol-Scand 75, no. 5 (1993): 347-349.
5. B. G. Ewigman, J. P. Crane, F. D. Frigoletto et al., "Effect of Prenatal
Ultrasound Screening on Perinatal Outcome," N Engl J Med 329, no. 12
6. C. A. Luck, "Value of Routine Ultrasound Scanning at 19 Weeks: A Four
Year Study of 8849 Deliveries," British Medical Journal 34, no. 6840
7. F. Y. Chan, "Limitations of Ultrasound," paper presented at Perinatal
Society of Australia and New Zealand 1st Annual Congress, Freemantle, 1997.
8. AIMS UK, "Ultrasound Unsound?," AIMS UK Journal 5, no. 1 (Spring 1993).
9. I. R. Brand, P. Kaminopetros, M. Cave et al., "Specificity of Antenatal
Ultrasound in the Yorkshire Region: A Prospective Study of 2261 Ultrasound
Detected Anomalies," Br J Obstet Gynaecal 101, no. 5 (1994): 392-397.
10. J. W. Sparling, J. W. Seeds, and D. C. Farran, "The Relationship of
Obstetric Ultrasound to Parent and Infant Behavior," Obstet Gynecol 72, no.
6 (1988): 902-907.
11. A. Brookes, "Women's Experience of Routine Prenatal Ultrasound,"
Healthsharing Women: The Newsletter of Healthsharing Women's Health
Resource Service (Melbourne, Australia) 5, no.s 3, 4 (December 1994-March
12. MIDIRS, Informed Choice for Professionals, Ultrasound Screening in the
First Half of Pregnancy: Is It Useful for Everyone? (UK: MIDIRS and the NHS
Centre for Reviews and Dissemination, 1996).
13. A. Saari-Kemppainen, O. Karjalainen, P. Ylostalo et al., "Ultrasound
Screening and Perinatal Mortality: Controlled Trial of Systematic One-stage
Screening in Pregnancy," The Lancet 336, no. 8712 (1990): 387-391.
14. See Note 12.
15. See Note 11.
16. D. Watkins, "An Alternative to Termination of Pregnancy," The
Practitioner 233, no. 1472 (1989): 990, 992.
17. See Note 12.
21. "American Institute of Ultrasound Medicine Bioeffects Report 1988," J
Ultrasound Med 7 (September 1988): S1-S38.
23. D. Liebeskind, R. Bases, F. Elequin et al., "Diagnostic Ultrasound:
Effects on the DNA and Growth Patterns of Animal Cells," Radiology 131, no.
1 (1979): 177-184.
24. M. H. Ellisman, D. E. Palmer, and M. P. Andre, "Diagnostic Levels of
Ultrasound May Disrupt Myelination," Experimental Neurology 98, no. 1
25. Brennan et al., "Shadow of Doubt," New Scientist 12 (June 1999): 23.
26. J. Testart, A. Thebalt, E. Souderis, and R. Frydman, "Premature
Ovulation after Ovarian Ultrasonography," Br J Obstet Gynaecol 89, no. 9
27. See Note 13.
28. R. P. Lorenz, C. H. Comstock, S. F. Bottoms, and S. R. Marx,
"Randomised Prospective Trial Comparing Ultrasonography and Pelvic
Examination for Preterm Labor Surveillance," Am J Obstet Gynecol 162, no. 6
29. J. Newnham, S. F. Evans, C. A. Michael et al., "Effects of Frequent
Ultrasound During Pregnancy: A Randomised Controlled Trial," The Lancet
342, no. 8876 (1993): 887-891.
30. S. B. Thacker, "The Case of Imaging Ultrasound in Obstetrics: A
Review," Br J Obstet Gynaecol 92, no. 5 (1985): 437-444.
31. J. P. Newnham et al., "Doppler Flow Velocity Wave Form Analysis in High
Risk Pregnancies: A Randomised Controlled Trial," Br J Obstet Gynaecol 98,
no. 10 (1991): 956-963.
32. C. R. Stark, M. Orleans, A. D. Havercamp et al., "Short and Long Term
Risks after Exposure to Diagnostic Ultrasound in Utero," Obstet Gynecol 63
33. J. D. Campbell et al., "Case-control Study of Prenatal Ultrasonography
in Children with Delayed Speech," Can Med Ass J 149, no. 10 (1993): 1435-
34. K. A. Salvesen, L. J. Vatten, S. H. Eik-nes et al., "Routine
Ultrasonography in Utero and Subsequent Handedness and Neurological
Development," British Medical Journal 307, no. 6897 (1993) 159-164.
35. H. Kieler, O. Axelsson, B. Haguland et al., "Routine Ultrasound
Screening in Pregnancy and the Children's Subsequent Handedness," Early
Human Development 50, no. 2 (1998): 233-245.
36. See Note 31.
37. K. A. Salvesen, L. S. Bakketeig, S. H. Eik-nes et al., "Routine
Ultrasonography in Utero and School Performance at Age 8-9 Years," The
Lancet 339, no. 8785 (1992):85-89.
38. H. Kieler, G. Ahlsten, B. Haguland et al., "Routine Ultrasound
Screening in Pregnancy and the Children's Subsequent Neurological
Development," Obstet Gynecol 91, no. 5 (1998): 750-756.
39. See Note 37.
40. H. B. Meire, "The Safety of Diagnostic Ultrasound," Br J Obstet
Gynaecol 94 (1987): 1121-1122.
41. K. J. W. Taylor, "A Prudent Approach to Ultrasound Imaging of the Fetus
and Newborn," Birth 17, no. 4 (1990): 218-223.
42. Barbara Katz Rothman, The Tentative Pregnancy: How Amniocentesis
Changes the Experience of Motherhood (New York: W. W. Norton, 1993).
For more information on ultrasound, see the following articles in past
issues of Mothering: "Ultrasound: More Harm Than Good?" no. 77; "The
Trouble with Ultrasound," no. 57; "How Sound Is Ultrasound?" no. 34;
"Ultrasound," no. 24; and "Diagnostic Ultrasound," no. 19.
Sarah Buckley (40) is a New Zealand-trained GP (family MD), and still in
training as partner to Nicholas. Mother of Emma (9), Zoe (6), and Jacob
(4), she is currently expecting her fourth baby and lives in Brisbane,
Australia, where she writes about pregnancy, birth, and parenting.
Shadow of a doubt
by Rob Edwards
ULTRASOUND SCANS can stop cells from dividing and make them commit suicide.
research team in Ireland say this is the first evidence that routine scans,
which have let doctors peek at fetuses and internal organs for the past 40
years, affect the normal cell cycle.
A team led by Patrick Brennan of University College Dublin gave 12 mice an
8-megahertz scan lasting for 15 minutes. Hospital scans, which reflect
inaudible sound waves off soft tissue to produce images on a monitor, use
frequencies of between 3 and 10 megahertz and can last for up to an hour
The researchers detected two significant changes in the cells of the small
intestine in scanned mice compared to the mice that hadn't been scanned.
and a half hours after exposure, there was a 22 per cent reduction in the
rate of cell division, while the rate of programmed cell death or
had approximately doubled.
Brennan believes there will be similar effects in humans. "It has been
assumed for a long time that ultrasound has no effect on cells," he says.
now have grounds to question that assumption."
Brennan stresses, however, that the implications for human health are
uncertain. "There are changes happening, but we couldn't say whether they
harmful or harmless," he explains. The intestine is a very adaptable organ
that can compensate for alterations in the cell cycle, says Brennan.
It is possible that the sound waves damage the DNA in cells, delaying cell
division and repair. Brennan suggests that ultrasound might be switching on
the p53 gene which controls cell deaths. This gene, dubbed "the guardian of
the genome", produces a protein that helps cells recognise DNA damage and
then either self-destruct or stop dividing.
Studies in the early 1990s by researchers at the University of Rochester in
New York and the Batelle Pacific Northwest Laboratories in Richland,
Washington, showed that tissue heating due to ultrasound can cause bleeding
in mouse intestines. Ultrasonographers now tune the power of scans to reduce
But Brennan's work is the first evidence that scans create changes in cells.
"Our results are preliminary and need further investigation," he says. The
team presented their results at the Radiology 1999 conference in Birmingham
last month and are now preparing them for submission to a peer-reviewed
Alex Elliott, a researcher in clinical physics at the University of Glasgow,
thinks that Brennan's results are important and should be followed with
further studies. "If the conditions of his experiments really compare to the
clinical use of ultrasound," he says, "we may have to review the current
From New Scientist, 12 June 1999
Here are some excerpts about ultrasound from "What Doctors Don't Tell You"
by Lynne McTaggart. "No well controlled study has yet proved that
routine scanning of prenatal patients will improve the outcome of
pregnancy" - official statement from American College of Obstetrics &
Gynecology in 1984
Some studies show that, with ultrasound, you are more likely to lose your
baby. A study from Queen Charlotte's and Chelsea Hospital in London found
that women having doppler ultrasound were more likely to lose their babies
than those who received only standard neonatal care (17 deaths to 7).
A Norwegian study of 2,000 babies found that those subjected to routine
ultrasound scanning were 30% more likely to be left-handed than those sho
weren't scanned. An Australian study demonstraates that frequent scans
increased the proportion of growth-restricted babies by a third, resulting
in a higher number of small babies. Exposure to ultrasound also caused
delayed speech, according to Canadian researcher Professor James Campbell.
The International Childbirth Education Association has maintained that
ultrasound is most likely to affect development (behavioral &
neurological), blood cells, the immune system, & a child's genetic makeup.
Besides the safety issue, there are considerable questions about accuracy.
There is a significant chance that your scan will indicate a problem when
there isn't one, or fail to pick up aa problem actually there. One study
found a "high rate" of false positives, 17% of the pregnant women scanned
were shown to have small-for-dates babies, when only 6% actually did - an
error rate of nearly one out of three. Another study from Harvard showed
that among 3,100 scans, 18 babies were erroneously labeled abnormal, and 17
fetuses with problems were missed.
this is from another list...
According to Anne Frye, midwife and author of "Understanding Lab Work in
the Childbearing Year" (4th Ed.)p. 405
Doppler Devices: Many women do not realize that doppler fetoscopes are
ultrasound devices. (apparently, neither do many care providers. Time
after time, women are assured by doctors and even some nurse midwives
that a doppler is not an ultrasound device.) . . . .
Not well publicized for obvious reasons, doppler devices expose the fetus
to more powerful ultrasound than real time (imaging) ultrasound exams.
One minute of doppler exposure is equal to 35 minutes of real time
ultrasound. This is an important point for women to consider when
deciding between an ultrasound exam and listening with a doppler to
determine viability in early pregnancy. . . . .
If you have a doppler, put it aside and make a concerted effort to learn
to listen yourself! Save your doppler for those rare occasions when you
cannot hear the heart rate late into pushing or to further investigate
suspected fetal death. " copyright l990, Anne Frye, B.H. Holistic
Personally, after 23 years of attending births, I would not permit a
doppler in my house if I were pregnant. You always know that something
is ultrasound because there will be "jelly" involved. If you want a
cheap listening device for the baby's heart just save the core from a
roll of toilet paper. Put one end on the lower belly and the other on
hubby's ear. If you want to know your baby is doing well, count the
fetal movements in a day. Starting at 9 a.m. count each time the baby
kicks. There should be l0 distinct movements by 3 p.m.
I think it's sad that some people will do anything to make a buck of the
huge pregnant market in North America. Please feel free to forward this
post on to any other lists.
Gloria Lemay, Vancouver BC
Wise Woman Way of Birth Courses
This made me wonder what ultrasound does to developing babies if it
can have such a drastic effect on a testicle.
Prenatal Testing and Informed Consent: Base Your Choices on the Evidence
By Peggy O'Mara
Issue 120, September/October 2003
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Vaccination Information & Choice Network, Nevada City CA & Wales UK
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Effect of diagnostic ultrasound during the fetal period on learning and
memory in mice
R. Suresh, a, , T. Ramesh Raoa, E.M. Davisa, Nikolai Ovchinnikova and
A. Mc Raea
Annals of Anatomy - Anatomischer Anzeiger
Article in Press, Corrected Proof
An experiment was conducted to find out whether in utero exposure to
diagnostic ultrasound leads to changes in postnatal behavior in adult
A total of 15 pregnant Swiss albino mice were exposed to diagnostic
levels of ultrasound (3.5 MHz, 65 mW/cm2, intensity(spatial
peak−temporal peak) (ISPTP)=1 mW/cm2, intensity(spatial
average−temporal average) (ISATA)=240 mW/cm2) for 30 min on day 14 or
16 of gestation. All exposed as well as control animals were left to
complete gestation and parturition. Their offspring were used in our
further studies. They were monitored during early postnatal life for
standard developmental markers (such as pinna detachment, eye opening
and fur development) and postnatal mortality was recorded up to 6
weeks of age. The litters were subjected to behavioral tests for
learning and memory at 4 months of age. Representative animals from
each group were sacrificed and the hippocampal region of the brain
was assayed for biogenic amines, noradrenaline, dopamine, serotonin
(5-HT) and 5-HT's metabolite, 5-hydroxy indoleacetic acid (5-HIAA),
in order to determine whether ultrasound exposure produced any
biochemical changes in the hippocampal region of the brain. Coronal
sections from the dorsal hippocampus from the representative animals
from each group were processed for staining and the number of neurons
Neither the standard developmental markers (such as pinna detachment,
eye opening and fur development) nor the postnatal mortality was
affected by ultrasound exposure. However, there was a significant
impairment in learning (hole board test) and memory functions
(shuttle box test) in both the exposure groups. Significant
reductions in the biogenic amines and the decrease in the neuronal
density were found only in day 14th pc ultrasound-exposed group
compared with the control animals. The 16th day exposure group is
relatively resistant to ultrasound-induced impairment of brain
The results suggest that the early fetal brain is highly susceptible
to induction of neurobehavioral changes by ultrasound exposure.
Keywords: Behavior; Gestation; Ultrasound; Neurotoxicity
Corresponding author. Tel.: +1 868 645 2640x4627(Off.)/1 868 645
2640x1863(Res.); fax: +1 868 662 9148.
Anatomy and Cell Biology Unit, Department of Preclinical Sciences,
Faculty of Medical Sciences, The University of The West Indies, St.
Augustine, Trinidad and Tobago, West Indies
Received 9 January 2007; accepted 13 May 2007. Available online 23
Above article received thanks to:
Sheri Nakken, former R.N., MA, Hahnemannian Homeopath
Vaccination Information & Choice Network, Nevada City CA & Wales UK
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Long-term effects of diagnostic ultrasound during fetal period on postnatal development and adult behavior of mouse
R. Suresha, P. Uma Devib, N. Ovchinnikova and A. McRaea
a Department of Anatomy, Faculty of Medical Sciences University of West Indies, St. Augustine, Trinidad and Tobago
b Department of Radiobiology, Kasturba Medical College, Manipal, India
Received 21 August 2001; accepted 18 January 2002. Available online 17 April 2002.
Pregnant Swiss albino mice were exposed to diagnostic levels of ultrasound (3.5 MHz, intensity 65 mW, ISPTP = 1 W/cm2,
ISATA = 240 W/cm2) for 10, 20 and 30 minutes on day 14 of gestation. Sham exposed controls were maintained for comparison.
Fifteen pregnant mice were exposed for each group. Exposed as well as control animals were left to complete gestation and
parturition. Ultrasound induced changes in maternal vaginal temperature was recorded. The changes in the physiological
reflexes and postnatal mortality up to 6 weeks of age were recorded. The litters were subjected to behavioral tests for
locomotor activity, learning and memory at 4 month and 1 year of age. Neither the physiological reflexes nor the postnatal
mortality was affected by ultrasound exposure. However, there was a noticeable impairment in both locomotor and
learning behavior even after a 10 min exposure, which further increased with increases in exposure time.
Thus the present study demonstrates the neurotoxicity of diagnostic ultrasound
and the high susceptibility of early fetal brain to induction of lasting detrimental changes by ultrasound exposure.
Effect of prenatal ultrasound exposure on adult behavior in mice.
Hande MP, Devi PU, Karanth KS.
Department of Radiobiology, Kasturba Medical College, Manipal, India.
Pregnant Swiss mice were exposed to diagnostic levels of ultrasound (3.5 MHz, Maximum acoustic output: ISPTP = 1 W/cm2 and ISATA = 240 mW/cm2, acoustic power = 65 mW) for 10 min on days 11.5 or 14.5 postcoitus (PC). At 3 and 6 months postpartum, offspring were subjected to the following behavioral tests: bright and dark arena test for locomotor/exploratory activity and passive avoidance test for learning and memory. Anxiolytic activity and latency in learning were noticed in the ultrasound-treated animals. The effect was more pronounced in the 14.5 days PC group than in the 11.5 days PC group. But memory was not affected in the ultrasound-exposed animals. There was a nonsignificant decrease in the total locomotor activity at 6 months of age in all the exposed animals. Thus, the present data demonstrate that exposure to diagnostic ultrasound during late organogenesis period or early fetal period in mice may cause changes in postnatal behavior as evidence by selected adult offspring behavioral tests. However, any conclusive statement in this regard should await results from more detailed investigations.
PMID: 8302245 [PubMed - indexed for MEDLINE]
On the "safety" amd "usefulness" of prenatal ultrasound
"Researchers at University College in Dublin told New Scientist magazine it is too early to tell if the changes they
found in the cells of mice are harmless or what the implications of the findings could be for humans."
The Dangers of Prenatal Ultrasound
Info about a book, Quotes, and Summaries of medical studies
on the dangers of Ultrasound for prenatal imaging of an unborn baby.
Behavioral teratologic effects of prenatal exposure to continuous-wave ultrasound in unanesthetized rats
Wiley InterScience Abstract of study preformed in 1994