Some moreand information on ultrasound.

[Guest guest]

p

Fri, 15 Apr 2005 01:31:06 -0000

More ultrasound dangers

 

 

 

Some more links and information on ultrasound.

 

 

Source: http://www.alternamoms.com/ultrasound.html

 

On the " safety " amd " usefulness " of prenatal ultrasound

 

 

 

Ultrasound may change baby's cell growth

June 9, 1999 (from CNN.com) Web posted at: 3:10 PM EDT (1910 GMT)

 

LONDON (Reuters) -- Ultrasound scans, routinely used to look at

internal organs and to monitor the growth of a developing fetus, can

stop cells from dividing normally, Irish scientists said Wednesday.

 

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.

 

" It has been assumed for a long time that ultrasound has no effect on

cells, " said Patrick Brennan, who led the research team. " We now have

grounds to question that assumption. "

 

During the study, the rate of cell division in mice that were given an

8 megahertz scan lasting 15 minutes was 22 percent lower than normal,

and the rate of cell death doubled.

 

Routine hospital scans use frequencies between 3 and 10 megahertz and

can last up to 60 minutes.

 

Brennan said the sound waves of the scans could be damaging the DNA in

cells, which could delay cell division and repair, or it might be

switching on p53, a tumor suppressor gene that controls cell death.

 

Cancer occurs when damaged cells multiply uncontrollably and form

tumors. Mutations in p53 are the commonest gene abnormalities seen in

human cancers.

 

" Our results are preliminary and need further investigation, " Brennan

told the magazine.

 

Other articles at New Scientist magazine

Fetuses can hear ultrasound examinations

Ultrasound scans may disrupt fetal brain development

 

 

 

 

 

Newnham, J.P., Evans, S.F., Michael, C.A., Stanley, F.J., & Landau,

L.I. (1993). Effects of Frequent Ultrasound During Pregnancy: A

Randomized Controlled Trial. The Lancet, 342(Oct.9), 887-891.

 

A study of over 1400 women in Perth, Western Australia compared

pregnant mothers who had ultrasound only once during gestation with

mothers who had five monthly ultrasounds from 18 weeks to 38 weeks.

They found significantly higher intrauterine growth restriction in

the intensive ultrasound group. These mothers gave birth to lower

weight babies.

 

The researchers concluded that prenatal ultrasound imaging and

Doppler flow exams should be restricted to clinically necessary

situations. This recommendation comes at a time when ultrasound during

prenatal visits has become increasingly popular and serves as a kind

of entertainment feature of office check-up visits.

 

 

Campbell, J.D., Elford, R.W. & Brant, R.F. (1993). Case-Controlled

Study of Prenatal Ultrasound Exposure in Children with Delayed Speech.

Canadian Medical Association Journal, 149(10), 1435-1440.

 

Delayed speech is not a pathological or organic syndrome but

developmentally defined symptom complex. Clinicians have noted an

increased incidence of delayed speech in pediatric patients.

 

This is a matched-case control study of 72 children 2 to 8 years old

presenting with delayed speech of unknown cause. The children were

measured for articulation, language comprehension, language

production, meta-linguistic skills, and verbal memory. When checked

for ultrasoundm exposure, the speech-delayed children were about twice

as likely to have been exposed to ultrasound than the matched

controls.

 

The authors believe that delayed speech is a sensitive measure

reflecting sub-optimal conditions for development. If ultrasound can

cause developmental delays, the authors are concerned about the

routine use of ultrasound and they warn against it.

 

 

Devi, P.U., Suresh, R., & Hande, M.P. (1995). Effect of fetal exposure

to ultrasound on the behavior of the adult mouse. Radiat Res (QMP),

141(3), 314-7.

 

Pregnant Swiss albino mice were exposed to diagnostic ultrasound.

There were significant alterations in behavior in all three exposed

groups as revealed by the decreased locomotor and exploratory activity

and the increase in the number of trials needed for learning. These

results indicate that ultrasound exposure during the early fetal

period can impair brain function in the adult mouse.

 

 

Hande, M.P., & Devi, P.U. (1995). Teratogenic effects of repeated

exposures to X-rays and/or ultrasound in mice. Neurotoxicol Teratol

(NAT), 17(2), 179-88.

 

Pregnant Swiss mice were exposed to ultrasound, x-rays, and

combinations of the two. Effects on prenatal development, postnatal

growth and adult behavior were studied. U + U group showed an increase

in percent growth retarded fetuses. The postnatal mortality was

significantly higher only in the U + U group. In the X + U group, the

exploratory activity was affected at 6 months of age. There was a

significant change in the locomotor activity with a reduction in the

total activity as 3 and 6 months of age in the U + U group. Latency in

learning capacity was also noticed in this group. The results indicate

that repeated exposures to ultrasound or its combination with X-rays

could be detrimental to the embryonic development and can impair adult

brain function when administered at certain stages of organogenesis.

 

 

 

From Ultrasound in Obstetrics: A Question of Safety

 

Millions of women and their unborn children are being exposed to

diagnostic ultrasound during pregnancy and childbirth without the

women being advised prior to exposure that there has been no well-

controlled scientific investigation carried out to study the delayed

long-term effects of ultrasound on human development.Ova, embryos and

fetuses are often exposed to prolonged sonography because the

physician or technician lacks sufficient expertise to evaluate what he

or she is seeing.

 

Recently the FDA yielded to pressure from industry and organized

medicine to relinquish control over the amount of sonic energy that

can be emitted by the new ultrasound devices used in obstetrics. The

new ultrasound machines will beep at certain levels of energy output

but essentially there will be little or no limit on the energy the

health care provider may choose to use.

 

Despite the fact that the FDA's Center for Devices and Radiologic

Health acknowledged the potential risks of ultrasound used in

obstetrics in its 1982 publication " An Overview of Ultrasound " , edited

by Stewart and Stratmeyer, there is no evidence that health care

providers are obtaining women's truly informed consent to the use of

ultrasound in pregnancy....

 

Numerous studies have been carried out to evaluate the effectiveness

of routine diagnostic ultrasound. None has shown the routine use of

diagnostic ultrasound to improve maternal and infant outcome over that

achieved when diagnostic ultrasound was used only when medically

indicated.

 

Are women overly concerned regarding the safety of ultrasound used in

obstetrics? A letter published in the July 1988 issue of the British

Journal of Obstetrics and Gynaecology, from Dr. Robert Bases, Chief of

the Radiobiology Section, Albert Einstein College of Medicine, calls

attention to the 1984 review by Stewart and Moore of over 700

publications since 1950 which demonstrate the present chaos in

delineating and controlling exposure conditions and the bewildering

range of ultrasound bioeffects. Bases states in his letter:

 

" The increased frequency of sister chromatid exchanges induced by

pulsed ultrasound in human lymphocytes, first described by Liebeskind

et al (1979), has been amply confirmed in reports from four

independent laboratories involving studies of pulsed as well as

continuous wave ultrasound (Haupt et al 1981; Ehlinger et al 1981;

Ozawa et al 1984; Stella et al 1984). Recently further evidence that

sister chromatid exchanges in human lymphocytes are induced by high-

intensity pulsed ultrasound has been presented by Barnett et al (1988)

, who are now able to confirm the previous results. "

 

" 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 recent 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. "

 

The implications of premature ovulation after ovarian ultrasonography,

reported by Testart et al, are disturbing. If ultrasound can affect

the adult ovary, what then is the effect of ultrasound on the ova of

the female fetus?

 

Even if we begin today to carry out a well-controlled investigation

into the delayed long-term effects of obstetric ultrasound it will be

20 or 30 years before we will know whether ultrasound will be the DES

of the next generation.

 

 

 

FromScreening Ultrasonography in Pregnancy

 

Routine third-trimester ultrasound examination of the fetus is not

recommended. There is insufficient evidence to recommend for or

against routine ultrasound examination in the second trimester in low-

risk pregnant women.

 

The most important potential benefit of ultrasound screening is

reduced perinatal mortality. Among the seven trials that evaluated an

ultrasound before 20 weeks (with or without additional late

ultrasound), only the Helsinki trial and a meta-analysis heavily

influenced by that trial's results were able to demonstrate a

statistically significant benefit in lowering perinatal mortality. Two

trials showed nonsignificant reductions in mortality while the

remaining four trials and another meta-analysis showed no mortality

benefit. In the Helsinki trial, the overall perinatal death rate was

4.6/1,000 deliveries (n = 18) in screened women versus 9.0/1,000

deliveries (n = 34) in unscreened women. In the experimental group, 11

induced abortions were performed because of ultrasound findings and

two babies died with major anomalies, compared to no abortions and 10

deaths with anomalies in the control group. There was no difference in

perinatal mortality when the induced abortions resulting from

ultrasound detection of congenital anomalies were included as deaths

in the analysis. The meta-analysis that reported a significant

mortality reduction included the four then-published trials that

compared routine to selective ultrasound scanning and that reported

number of pregnancies, deliveries, and perinatal deaths. It also

evaluated the live birth rate, which takes into account induced

abortions for malformations, and found it to be identical in the

screened and control groups. The largest trial to date, the RADIUS

trial randomized 151 low-risk pregnant women to routine ultrasound

scans at 15-22 and 31-35 weeks of gestation or to usual care, which

included ultrasounds performed for indications that developed after

randomization. The risk of fetal or neonatal death was the same in the

screened (0.6%, n = 52) and control (0.5%, n = 41) groups. Including

induced abortions for fetal anomalies (9 vs. 5 in the routinely and

selectively screened groups, respectively) did not affect these

estimates.

 

While ultrasound before 20 weeks allows earlier detection of fetal

structural malformations, it is not clear that this results in

improved outcome. In the Helsinki trial, early detection led to an

increased rate of elective abortions (2.7/1,000 screened women vs. 0/

1,000 control women) and therefore to reduced perinatal deaths (see

above).On the other hand, in the RADIUS trial,38 screening had no

statistically significant effect on the rate of induced abortion (n =

9 or 1.2/1,000 screened women compared to n = 4 or 0.5/1,000 controls)

.. Although early detection might theoretically improve survival for

infants with fetal anomalies if they could be delivered at tertiary

care centers capable of immediate medical and surgical intervention,

no significant effects of early detection on overall perinatal

mortality, or on survival rates among infants born with acute life-

threatening anomalies or with any major anomalies, were seen in the

RADIUS trial.Other trials of routine ultrasound before 20 weeks have

detected too few (i.e., 0-2) malformations to allow meaningful

comparisons of outcomes. None of the trials has evaluated whether

routine screening improves outcomes in newborns with nonlethal

anomalies.

 

A National Institutes of Health consensus development conference

recommended that ultrasound imaging during pregnancy be performed only

for a specific medical indication and not for routine screening. This

is also the position of the American College of Obstetricians and

Gynecologists. The Canadian Task Force on the Periodic Health

Examination found fair evidence to recommend a single second-trimester

ultrasound examination in women with normal pregnancies, but concluded

that there was insufficient evidence to recommend the inclusion or

exclusion of routine serial ultrasound screening for IUGR in normal

pregnancies.

 

 

 

Breastfeeding ~ Circumcision ~ Ultrasounds ~ Vaccination ~ Glossary

Birth Stories ~ The Bookshelf ~ Pregnancy Guide ~ Midwives ~ Doulas

~ Home