PREGNANCY MATTERS
UUltrasound: high-frequency sound
waves that travel at 10 to 20 million
cycles per second. The pattern of
echo waves creates a picture of tissue
and bone.
In 1987, UK radiologist H.D. Meire,
who had been performing pregnancy
scans for 20 years, commented, “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”.
Routine prenatal ultrasound (RPU)
actually detects only between 17 and
85 percent of the 1 in 50 babies who
have major abnormalities at birth.
RPU can identify a low-lying placenta
(placenta previa). However,
19 of 20 women who have placenta
previa detected on an early scan
will be needlessly worried: the
placenta will effectively move
up without causing problems at
the birth. Furthermore, detection
of placenta previa by RPU has
not been found to be safer than
detection in labor.
The American College of Obstetricians
has concluded that “in a population
of women with low-risk pregnancies,
neither a reduction in perinatal
morbidity and mortality nor a lower
rate of unnecessary interventions
can be expected from routine diagnostic
ultrasound. Thus ultrasound
should be performed for specific
indications in low-risk pregnancy.
Effects of ultrasound include cavitation,
a process wherein 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. These violent
processes may be produced by
microsecond pulses of the kind
which are used in medical diagnosis.”
(American Institute of Ultrasound
Medicine Bioeffects Report 1988).
The significance of cavitation in
human tissue is unknown.
Studies have suggested that these
effects are of real concern in living
tissues:
• Cell abnormalities caused by
exposure to ultrasound were seen
to persist for several generations.
• In newborn rats (similar stage
of development as human fetuses
at four to five months in utero),
ultrasound can damage the myelin
that covers nerves.
• Exposing mice to dosages typical
of obstetric ultrasound cased a
22% reduction in the rate of cell
division and doubling of the rate
of aptosis (programmed cell death),
in the cells of the small intestine.
• Two long-term randomized
controlled trials comparing
exposed and unexposed childrens’
development at eight to nine years
old found no measurable effect
from ultrasound. However, the
authors comment that intensities
used today are many times higher
than there were in 1979 and 1981.
—Excerpted from
“Ultrasound Scans: Cause for Concern”
References available online:
www.icpa4kids.com
