Bad Vibrations? Ultrasound disturbs mouse brains
Christen Brownlee
Prolonged and frequent use of fetal ultrasound might lead to abnormal brain development, a study in mice suggests. The finding sounds a cautionary note for pregnant women getting the commonplace procedure.
In that technique, an ultrasound probe sends high-frequency sound waves into the abdomen of a pregnant woman. The waves bounce back to detectors, creating images of the fetus. Doctors use the pictures to check for birth defects and to assess a fetus' size and movements. Many women also undergo ultrasounds to create collections of early baby pictures.
Ultrasound has generally been regarded as safe. However, a few studies have suggested that it might cause neurological changes, such as delayed speech or an increase in left-handedness. Researchers hadn't studied how the number or duration of ultrasound procedures affects neurons growing in the fetal brain, says neuroscientist Pasko Rakic of Yale University.
Neurons are created in discrete places within the brain as it develops, and they then travel to the brain's outer layers. Rakic and his colleagues study this process, which is known as neural migration.
To determine whether ultrasound affects neural migration, the team worked with mice at a late point in pregnancy, when new fetal neurons have to migrate a long distance to reach the brain's outer layers.
The researchers injected the animals with a chemical that marks newborn neurons and then applied ultrasound to the bellies of some of the animals over the next 3 days. The ultrasound was administered to each pregnant mouse in multiple sessions that totaled 5 to 420 minutes. With the machine turned off, the scientists touched other mice with the ultrasound probe for the same amounts of time. A third group of animals received no procedure at all.
After the mouse pups were born, the team examined brain slices. In animals whose mothers had had ultrasound sessions that added up to 30 minutes or more, the scientists found that a significant number of neurons destined for the brain's outer layers of gray matter had become improperly embedded in inner layers of white matter.
The number of misplaced neurons increased with the total time that a newborn mouse's mother had spent receiving ultrasound. In contrast, the brains of newborns whose mothers had had the sham procedure typically resembled those whose mothers had had no procedure, Rakic's team reports in an upcoming Proceedings of the National Academy of Sciences.
"When cells are in the wrong place, they might affect function of the cerebral cortex," which in people controls such higher brain functions as language and movement, says Rakic. "We just don't know yet what this could do."
He and his team plan to conduct studies that will determine whether the results hold up in nonhuman primates.
Rakic cautions that some women might be getting excessive sonography. He's especially concerned about so-called keepsake ultrasounds, which are often performed by untrained technicians in nonclinical settings, such as shopping malls.
The mouse results reinforce guidelines set by the Food and Drug Administration, says pediatric neurologist Verne Caviness of Massachusetts General Hospital in Boston. "The basic guidelines in this country suggest using ultrasound as little as possible," he says. "Baby pictures aren't a justifiable use for this technology."
If you have a comment on this article that you would like considered for publication in Science News, send it to editors@sciencenews.org. Please include your name and location.
To subscribe to Science News (print), go to www.kable.com/pub/scnw/ subServices.asp.
To sign up for the free weekly e-LETTER from Science News, go to www.sciencenews.org/pages/su...form.asp.
References:
Ang Jr., E.S.B., . . . and P. Rakic. In press. Prenatal exposure to ultrasound waves impacts neuronal migration in mice. Proceedings of the National Academy of Sciences. Available at www.pnas.org/cgi/doi/10.....0605294103.
Further Readings:
Devi, P.U., R. Suresh, and M.P. Hande. 1995. Effect of fetal exposure to ultrasound on the behavior of the adult mouse. Radiation Research 141(March):314-317. Abstract.
Kieler, H., et al. 2005. Does prenatal sonography affect intellectual performance? Epidemiology 16(May):304-310. Abstract.
______. 2002. First trimester ultrasound scans and left-handedness. Epidemiology 13(May):370.
Newnham, J.P., et al. 1993. Effects of frequent ultrasound during pregnancy: A randomised controlled trial. Lancet 342(Oct. 9):887-891. Abstract available at dx.doi.org/10.1016/0140-6736(93)91944-H.
Stark, C.R., et al. 1984. Short- and long-term risks after exposure to diagnostic ultrasound in utero. Obstetrics & Gynecology 63(February):194-200. Abstract available at www.greenjournal.org/cgi/con...3/2/194.
Tarantal, A.F., and A.G. Hendrickx. 1989. Evaluation of the bioeffects of prenatal ultrasound exposure in the cynomolgus macaque (Macaca fascicularis): I. Neonatal/infant observations. Teratology 39(February):137-147. Abstract available at dx.doi.org/10.1002/tera.1420390206.
Sources:
Verne S. Caviness
Massachusetts General Hospital
Kennedy 901
55 Fruit Street
Boston, MA 02114
P. Ellen Grant
Massachusetts General Hospital
Neuroradiology Division
55 Fruit Street
Boston, MA 02114
Pasko Rakic
Department of Neurobiology
Yale University
333 Cedar Street
New Haven, CT 06510
Christen Brownlee
Prolonged and frequent use of fetal ultrasound might lead to abnormal brain development, a study in mice suggests. The finding sounds a cautionary note for pregnant women getting the commonplace procedure.
In that technique, an ultrasound probe sends high-frequency sound waves into the abdomen of a pregnant woman. The waves bounce back to detectors, creating images of the fetus. Doctors use the pictures to check for birth defects and to assess a fetus' size and movements. Many women also undergo ultrasounds to create collections of early baby pictures.
Ultrasound has generally been regarded as safe. However, a few studies have suggested that it might cause neurological changes, such as delayed speech or an increase in left-handedness. Researchers hadn't studied how the number or duration of ultrasound procedures affects neurons growing in the fetal brain, says neuroscientist Pasko Rakic of Yale University.
Neurons are created in discrete places within the brain as it develops, and they then travel to the brain's outer layers. Rakic and his colleagues study this process, which is known as neural migration.
To determine whether ultrasound affects neural migration, the team worked with mice at a late point in pregnancy, when new fetal neurons have to migrate a long distance to reach the brain's outer layers.
The researchers injected the animals with a chemical that marks newborn neurons and then applied ultrasound to the bellies of some of the animals over the next 3 days. The ultrasound was administered to each pregnant mouse in multiple sessions that totaled 5 to 420 minutes. With the machine turned off, the scientists touched other mice with the ultrasound probe for the same amounts of time. A third group of animals received no procedure at all.
After the mouse pups were born, the team examined brain slices. In animals whose mothers had had ultrasound sessions that added up to 30 minutes or more, the scientists found that a significant number of neurons destined for the brain's outer layers of gray matter had become improperly embedded in inner layers of white matter.
The number of misplaced neurons increased with the total time that a newborn mouse's mother had spent receiving ultrasound. In contrast, the brains of newborns whose mothers had had the sham procedure typically resembled those whose mothers had had no procedure, Rakic's team reports in an upcoming Proceedings of the National Academy of Sciences.
"When cells are in the wrong place, they might affect function of the cerebral cortex," which in people controls such higher brain functions as language and movement, says Rakic. "We just don't know yet what this could do."
He and his team plan to conduct studies that will determine whether the results hold up in nonhuman primates.
Rakic cautions that some women might be getting excessive sonography. He's especially concerned about so-called keepsake ultrasounds, which are often performed by untrained technicians in nonclinical settings, such as shopping malls.
The mouse results reinforce guidelines set by the Food and Drug Administration, says pediatric neurologist Verne Caviness of Massachusetts General Hospital in Boston. "The basic guidelines in this country suggest using ultrasound as little as possible," he says. "Baby pictures aren't a justifiable use for this technology."
If you have a comment on this article that you would like considered for publication in Science News, send it to editors@sciencenews.org. Please include your name and location.
To subscribe to Science News (print), go to www.kable.com/pub/scnw/ subServices.asp.
To sign up for the free weekly e-LETTER from Science News, go to www.sciencenews.org/pages/su...form.asp.
References:
Ang Jr., E.S.B., . . . and P. Rakic. In press. Prenatal exposure to ultrasound waves impacts neuronal migration in mice. Proceedings of the National Academy of Sciences. Available at www.pnas.org/cgi/doi/10.....0605294103.
Further Readings:
Devi, P.U., R. Suresh, and M.P. Hande. 1995. Effect of fetal exposure to ultrasound on the behavior of the adult mouse. Radiation Research 141(March):314-317. Abstract.
Kieler, H., et al. 2005. Does prenatal sonography affect intellectual performance? Epidemiology 16(May):304-310. Abstract.
______. 2002. First trimester ultrasound scans and left-handedness. Epidemiology 13(May):370.
Newnham, J.P., et al. 1993. Effects of frequent ultrasound during pregnancy: A randomised controlled trial. Lancet 342(Oct. 9):887-891. Abstract available at dx.doi.org/10.1016/0140-6736(93)91944-H.
Stark, C.R., et al. 1984. Short- and long-term risks after exposure to diagnostic ultrasound in utero. Obstetrics & Gynecology 63(February):194-200. Abstract available at www.greenjournal.org/cgi/con...3/2/194.
Tarantal, A.F., and A.G. Hendrickx. 1989. Evaluation of the bioeffects of prenatal ultrasound exposure in the cynomolgus macaque (Macaca fascicularis): I. Neonatal/infant observations. Teratology 39(February):137-147. Abstract available at dx.doi.org/10.1002/tera.1420390206.
Sources:
Verne S. Caviness
Massachusetts General Hospital
Kennedy 901
55 Fruit Street
Boston, MA 02114
P. Ellen Grant
Massachusetts General Hospital
Neuroradiology Division
55 Fruit Street
Boston, MA 02114
Pasko Rakic
Department of Neurobiology
Yale University
333 Cedar Street
New Haven, CT 06510
posted by:
|
Oregon
|
-
Re: Ultrasound could be bad
Tue, September 5, 2006 - 5:42 PMthanks for spreading the word...it definately sounds harmful and i have had a few ultrasounds done before and every time the baby puts its hands up to its ears like the waves are bothering them...these ultrasounds are being done way too much even when the pregnancy is healthy...
-
WHAT????
Wed, September 6, 2006 - 1:44 PMRakic cautions that some women might be getting excessive sonography. He's especially concerned about so-called keepsake ultrasounds, which are often performed by untrained technicians in nonclinical settings, such as shopping malls
OMG!!! Are people completely insane???!!!
I only allowed ultrasound w/2 of 5 of my children, one was only near early birth to check for fluid for an amnio, and this last one because they were concerned w/maternal age and I ended up w/GD. But have it done by untrained people!!! Technicians can set it to break apart kidney stones for crying out loud, that's right up there w/letting anybody use lasers!
E
-
Re: Ultrasound could be bad
Mon, December 25, 2006 - 10:49 PMThis mouse testing was a good follow-up to a retrospective study done in Sweden a few years ago on humans. They examined thousands of adult men who had been exposed to routine prenatal ultrasounds (they checked records from 1985 on to locate qualified participants), and found statistically-significant detrimental behavioral changes similar to those found in fetal alcohol syndrome, including a large increase in left-handedness.
Some folks say "so what?", not realizing that natural left-handedness is fine, and often lefties are gifted, but - if a person who was naturally predisposed to be right-handed is instead left-handed, it is often a sign of certain types of brain damage. So the fact was established by the Swedish study that prenatal ultrasound does have a quantifiable damaging effect on the human brain, resulting in various altered behaviors. The mouse study confirms the probable mechanism of the damage, that neurons are permanently displaced or halted while in the act of growing toward the outer areas of the brain.
Once again, we can create technology faster than we seem to gain the amount of healthy caution needed to use it safely. We take life-saving interventions and turn them into life-altering interferences. Someday we might grow up, hopefully before we kill ourselves.
hugs,
Grandma
