Aug 30 2011
Are Prenatal Ultrasounds Dangerous?
Several questionable sources are spreading alarms about the possible dangers of prenatal ultrasound exams (sonograms). An example is Christine Anderson’s article on the ExpertClick website. In the heading, it says she “Never Liked Ultrasound Technology.”
[She] has never been sold on the safety using Ultrasounds for checking on the fetuses of pregnant women, and for the last decade her fears have been confirmed with a series of studies pointing to possible brain damage to the babies from this technology.
Should We Believe Her?
Should we avoid ultrasounds because Anderson never liked them? Should we trust her judgment that her fears have been confirmed by studies? Who is she?
“Dr.” Christine Anderson is a pediatric chiropractor in Hollywood who believes a lot of things that are not supported by science or reason. Her website mission statement includes
We acknowledge the devastating effects of the vertebral subluxation on human health and therefore recognize that the spines of all children need to be checked soon after birth, so they may grow up healthy.
It also states that “drugs interfere… and weaken the mind, body, and spirit.” Anderson is a homeopath, a craniosacral practitioner, a vegan, and a yoga teacher. She advises her pregnant patients to avoid toxins by only drinking filtered water and only eating organic foods. She sells her own yoga DVD.
In her own pregnancies she refused ultrasound and other prenatal screening tests. This was her idiotic reasoning:
I trusted in my body’s innate wisdom that if the pregnancy was moving forward, then everything was going OK in my baby’s development.
Apparently on her planet if a pregnancy has not spontaneously aborted that means the baby is developing normally, and no abnormal child is ever born. And perhaps all the children are above average?
She believes in many alleged benefits of chiropractic that are not substantiated by any evidence. She says that our emotions create chemical changes in our bodies that can affect our developing babies; and that chiropractic helps to keep those feel good chemicals flowing freely. She believes that chiropractic frees up any interference to the nervous system and since the nervous system controls all the functions in the body, chiropractic manipulations allow the organs to optimally process any toxins they encounter. She believes getting regular chiropractic care reduces labor times.
Based on this, I am not impressed by her medical judgment or her understanding of biology or science, but that doesn’t necessarily mean she is wrong about ultrasound. What does she say?
Alleged Risks of Ultrasound According to Anderson
- Ultrasound heats the tissue and researchers suspect that the waves cause small local gas pockets which vibrate and collapse called cavitation. The gas can reach up to temperatures of thousands of degrees (Celsium) [sic] leading to production of potentially toxic chemical reactions.
- Studies done on mice have shown intestinal bleeding caused by changes in the cells. Scientists conclude that there would be similar effects in humans.
- Ultrasound has been linked to the following abnormalities:
- Left handedness in children who are supposed to be right-handed. Although there is nothing inherently wrong with being left handed, the change is attributed to a subtle damage to the brain. Males are more affected than female fetuses, probably because the male brain develops later.
- Early labor, premature birth, miscarriage, low birth weight, poorer health at birth, and perinatal death.
- Increased learning disabilities, epilepsy, delayed speech development, dyslexia
She also alleges that no studies have been done to prove the safety of these devices. This is demonstrably false.
Elsewhere, prenatal ultrasound exposure has even been accused of causing autism although a study found no association.
Risks According to Scientists
Obstetricians and radiologists who have evaluated the peer-reviewed literature have found no evidence of harm except for an apparent correlation between ultrasound exposure and left-handedness (in males only!). Such odd-sounding correlations are usually not significant, and are mostly good for a chuckle.
Experts place little reliance on the mouse studies, since the dosages tested were higher than what humans are exposed to and since no corresponding clinical consequences have been detected in humans. Nevertheless, they acknowledge theoretical reasons for concern, and they recommend that medically unnecessary ultrasounds be avoided under the precautionary principle.
Does Routine Ultrasound Affect Outcomes?
A large study (15,530 women) published in The New England Journal of Medicine found that routine screening did not reduce perinatal morbidity and mortality. There were no significant differences in the rate of preterm delivery, distribution of birth weight, or outcomes within the subgroups of women with multiple gestations, small-for-gestational-age infants, and post-date pregnancies. Finally, the detection of major anomalies by ultrasound examination did not alter outcomes. The authors pointed out that routinely screening more than 4 million pregnant women annually in the United States at $200 per scan would increase costs by more than $1 billion.
A Finnish study found that perinatal mortality was significantly lower in the screened than in the control group (4.6/1000 vs 9.0/1000); but this was attributed to improved early detection of major malformations which led to induced abortion. All twin pregnancies were detected before the 21st gestational week in the screening group compared with 76.3% in the control group; perinatal mortality in the small series of twins was 27.8/1000 vs 65.8/1000, respectively.
Caveats: These studies did not look for long-term consequences like learning disabilities. And there are other considerations besides morbidity and mortality. Ultrasound can reassure patients or allow them to plan ahead for multiple births or abnormal infants, and it can guide obstetric management.
Reasons for Doing Ultrasounds
Ultrasounds can detect fetal abnormalities and can help guide obstetric care by detecting problems like multiple fetuses and placenta previa. There are many legitimate reasons for doing them, especially in high-risk pregnancies or when a specific problem is suspected.
Reasons for Not Doing Routine Ultrasounds
False alarms can be raised. Apparent abnormalities may cause worry but turn out not to be significant. Placenta previa detected early in pregnancy frequently resolves before delivery.
There is no way to completely rule out the possibility of a low risk of long-term consequences. Trying to identify such consequences by even the most careful epidemiologic studies is fraught with pitfalls, since if you look for every possibility you will inevitably find a few spurious correlations. Experts agree that routine ultrasound screening is not necessary in low-risk pregnancies and that ultrasounds for nonmedical reasons should be discouraged.
Some nonmedical uses are particularly objectionable. Ultrasounds are being used in India and elsewhere to determine sex for the purpose of aborting undesired female fetuses. Ultrasound is being commercially promoted for “keepsake” pictures and movies like this 5 minute video. Tom Cruise was roundly criticized by doctors for buying his own ultrasound machine for home use.
Conclusion
There is no reason to fear prenatal ultrasounds that are ordered by science-based medical professionals and performed by qualified technicians, but it seems prudent to exercise caution and not do them for frivolous reasons.
Considering that Anderson practices homeopathy, subluxation-based chiropractic, and craniosacral therapy, disparages drugs, and manipulates the spines of newborn infants, I think her own practices are far more worrisome than the ultrasounds she fears.
If one thinks of how many mothers and babies have been saved as a result of ultrasound technology, I would be prepared to accept a significantly higher risk to protect myself and my child.
Anyway, if this were true, we would be seeing significant increases in learning disabilities and brain damage as countries become increasingly developed. And that is simply not true.
“[N]o evidence of harm except for an apparent correlation between ultrasound exposure and left-handedness (in males only!).”
What is the differential incidence of sinistromanuality in ultrasound / non-ultrasound populations?
Agreement:
I am an ex-Homeopath and ex-Acupuncturist. This logic permeate much of alternative medicine and is very wrong. Experience teaches that — unless one is very lucky.
Question:
You go through re-assuring us that the mice experiments don’t mean anything, that left-handed issues are just odd. Then you tell us not to do US for “non-medical reasons” but the reasons you give are cost and unnecessary worry. (which I agree with)
We have our own U/S tech in our office (Urology) and pregnant staff are getting U/S frequently for monthly “my cute baby” scrapbooks.
So there is not cost to them and there is no unnecessary worry for the most part (just unnecessary obsession). So my question: at what point do you think too much U/S is too much for physical health reasons. Is that question important? Or are all your reasons essentially social (cost) and psychological?
PS – Thank you kindly for the article!! I learned a lot. This site has very generous authors.
Sabio: The other concern is those places in malls who offer “fun” ultrasounds–the ones that say “not for diagnostic purposes.” In my mind, that’s both frivolous and potentially hazardous, since (AIUI) these places are not regulated.
I have never worried about my numerous ultrasounds or non-stress tests other than the possibility of a bad result, but something about the casual use of ultrasound rubs me the wrong way. I don’t really like the “we don’t know if it’s 100% safe” argument, since it skews close to the “If we don’t know it’s safe for sure, we shouldn’t do it!” argument. But it does seem to me like we should treat a medical technique with a little bit of respect. Maybe it’s just because I don’t get the luxury of treating these tests casually (those twice a week NSTs are one of your less fun uses of the technology…)
I was high-risk and had over 20 ultrasounds for a pregnancy that ended up being only 27 weeks long (but am happy to report ended in a little girl now 3 years old and healthy). I researched the risks of ultrasound along the way and could find none in my pubmed wanderings aside from mouse studies (as mentioned above).
What I can say from my experience though, is that when things are going wrong in pregnancy (I had bleeding throughout) there is nothing that will calm a woman’s fears like seeing her baby alive and well by ultrasound.
Ultrasounds find many children that will be born with cleft lip and palate. I believe this is beneficial to both the parents in the child, since it allows the parents time to acclaimate themselves emotionally to the idea of the child’s difference and see it for the treatable, managable condition that it is.
It allows parent’s to take time during the later prenatal period to prepare for differences in feeding and familiarize themselves with the cleft team options in their area. Once parents are familiar with the treatment, standard care for children with clefts and have spoken (in person or online) with other parents of children with clefts they are free to enjoy the birth and infancy of their child much more fully than if they were presented with the cleft at birth. It seems to me this would result in healthier children and parents, but I’m not sure what the research (if any) indicates.
Well thank you Ms. Anderson (I can’t bring myself to call you a Doctor) for suggesting that because I am left handed that I must be defective. I realize you didn’t use the actual term “defective”, but when you suggest being left handed is due to “subtle damage to the brain”, you are essentially telling me I am brain-damaged.
Nice.
I wonder if there is a Chiropractic treatment that could fix my condition and allow me to find my true inner right-handedness that I have been missing for almost four decades.
Seriously… how to people continue to fall for this garbage? It reminds me of the old George Carlin quote – “think about how stupid the average person is, and then realize that half of ‘em are stupider than that”.
@costner, being left handed I had the same reaction. But what really got me was the ‘left-handedness in children who were supposed to be right-handed’ comment. How, exactly, do you figure out that a child was ‘supposed to be right-handed’?
I wonder if there’s some interesting tests and ‘treatments’ behind that phrase.
Gee, and to think of all the creative high-achievers who are left handed..makes me as a righty feel dreadfully average. How could left handedness prossibly be a curse.
CarolMon 30 Aug 2011 at 11:21 am
“Gee, and to think of all the creative high-achievers who are left handed..makes me as a righty feel dreadfully average. How could left handedness prossibly be a curse.”
It can be a bit of a drag to live in a right handed world, right-handed spiral notebooks, right handed desks and the whole writing left to right, were always my pet peeves… guess they just don’t make curses like they used to.
@Sabio Lantz,
“you tell us not to do US for “non-medical reasons” but the reasons you give are cost and unnecessary worry.”
No, the reasons experts give for not doing unnecessary ultrasounds are the concerns raised by the animal studies, the possibility of localized overheating, etc. I think everyone agrees that any risk would be minimal even in the worst case, but because of the precautionary principle, most doctors think it is better to avoid even a minimal possible medical risk if there is no medical benefit.
Cool post. when CAM has a problem with ultrasound, you just have to ask, ‘what next.’ They could ban the giving of teddy bears and cards at the delivery room.
There is nothing wrong with being left-handed. However, it can happen that a neurological insult can lead to a subtle developmental problem which will manifest itself in various ways, and one of those is left-handedness. The left-handedness is just a sign of the harm. Analogy: Some people have slow-growing hair, and others fail to have hair growth due to radiation exposure. Baldness is not a problem in itself, but is present with enough radiation exposure.
The problem with ultrasound is when it is used to detect reasons for abortion. Some in the disability-rights movement are bothered that pre-born children are being aborted merely for having a prenatally diagnosed birth defect, including cleft palate.
Ultrasound is being used to determine whether the pre-born baby is male or female, so gender selection by abortion can be practiced: a resercher “G Lin” presented “Low Female-Male Birth Gender Ratios Become More Widespread in California as Keepsake Ultrasound Proliferates” at the 2011 American Institute of Ultrasound in Medicine Annual Convention.
Ultrasound is practically invaluable for prenatal surgery. Prenatal surgery is an amazing growing field.
If ultrasound itself harmed the developing human in utero, there would be smoe kind of signal to discern at this point. It would be valuable data to have resch done on mice to figure out the degree that repeat ultrasound, up to some level like double the number of sessions a human might get in some extreme circumstance, at whatever might be the full power.
The idea that our bodies have some sort of “innate wisdom”, along with the myth that all low-risk pregnancies end in a live birth and a healthy baby, both need to die.
My first son died the day before his due date because the midwife didn’t want to do an “unnecessary” ultrasound at 38 weeks even though I measured 4 weeks small.
My second son had oligohydramnios – diagnosed at 34 weeks during one of many weekly ultrasounds – and labor was induced at 38 weeks, when the levels went down to 2cm. He was born healthy. He is right-handed btw. I am convinced my first son died of some complication resulting from oligohydramnios, which would have been detected on an ultrasound, and he would be alive today.
I think one ultrasound per trimester should become routine. And the next woo advocate who tells me to trust nature’s wisdom is going to get slapped. Nature delivers stillborn babies.
Don’t chiropractors like to take full body skeletal x-rays like they are going out of style? Kind of curious that Christine Anderson denigrates the use of ultrasound but endorses and uses x-rays prior to most chiropractic treatment to “treat” what is certainly a non-medical condition, bad subluxations.
I was curious as to the ultrasound left handed result and found this abstract.
http://onlinelibrary.wiley.com/doi/10.1002/uog.9055/abstract
I looked and didn’t find very much on the incidence of left-handedness in the population, but some that indicates pretty strong season of birth effect. There is also some sparse data on how the incidence has changed over time.
http://www.ncbi.nlm.nih.gov/pubmed/19142795
Humans are mostly bilaterally symmetric. There are important asymmetries in many of the major internal organs, brain, heart, gut, liver. Presumably there are symmetry breaking events at certain critical times in utero that produce these asymmetries. Characteristic symmetry breaking needs a characteristic asymmetric signal of the right length scale at the time of symmetry breaking. Presumably that length scale is on the order of a few microns, the size of one or a few cells.
The sound used is on the order of 5.8 MHz, so the wavelength in water is ~ 260 microns. When the sound reflects from internal structures, the reflection does put an asymmetric signal on what ever structures are doing the reflecting, but it is kind of hard to imagine what physiology would do that. I am pretty sure it would have to depend on fetal orientation to the ultrasonic signal.
Left-right-handedness symmetry breaking is probably pretty subtle if there is a significant effect of season of birth on it and if it has changed significantly in the past several hundred years.
“no evidence of harm except for . . . left-handedness (in males only!). Such odd-sounding correlations . . . are mostly good for a chuckle.”
which I had. my husband and I are both left handed, and as our daughter indicated being left handed, I guess I’m suppose to wonder is it genes or US?
personally, I loved having the US, it was just amazing. for every low-plausibility, small correlation-only child out there with a learning disorder the mother claims unscientifically on the US, there are how many other babies (way more) who would have benefited from one or more US? My friend recently lost her premature baby; she had a number of risk factors, and a 2nd US a few weeks after her 20 wk one would have shown the failing placenta and no fluid. it’s anecdotal, and we don’t know the outcome if she had been screened again, but all those mothers in 3rd world countries could sure benefit from having one.
“The problem with ultrasound is when it is used to detect reasons for abortion. Some in the disability-rights movement are bothered that pre-born children are being aborted merely for having a prenatally diagnosed birth defect, including cleft palate.”
Medvstherapy, do you have any sources to support this statement?
I’m not aware that aborting due to a diagnoses of cleft lip and palate alone happens in the U.S.. One consideration, I believe*, is that clcp is not diagnosed on ultrasound until the second trimester.
@daedalus,
Any historical comparisons of left-handedness rates must take into account that left-handedness was stigmatized and it used to be customary to discourage left-handedness by forcing children to use their right hands.
“Elsewhere, prenatal ultrasound exposure has even been accused of causing autism although a study found no association.”
As a parent of twins with autism, I wondered about the possible impact of the frequent prenatal ultrasounds our children were exposed to in utero. In our case, frequent ultrasounds were necessary not only because of the twin pregnancy, but also because my wife developed cervical incompetence necessitating a cerclage and bedrest the last few months of the pregnancy.
I think there is published data on a higher incidence of autism in twin pregnancies, and in our case there were other obvious factors that could have influenced neural development aside from the frequent ultrasounds. The study Dr. Hall linked to did not look at “high risk” pregnancy or multiple gestations, so I would say the jury is still out for those populations.
Certainly the wealth of the data in the literature for the etiologic basis of autism suggests strong genetic factors, though I would agree with the points raised by daedalus in numerous threads that there probably are important gene-environment interactions that dictate the phenotype.
I will say this – if we hadn’t been getting the frequent ultrasounds, we probably would have lost both of our children. My wife was completely asymptomatic when the cervical incompetence was detected. In retrospect, would I have changed anything? No way.
Michele: Anecdotally, I am aware of 2 cases where parents aborted for cleft lip and palate. This proves absolutely nothing about frequency, but I also doubt I managed to hear about the only two cases. OTOH, I know people who had it prenatally diagnosed, and did not abort. I certainly don’t think it’s like Down Syndrome, where people who are unwilling to abort seem more likely to avoid screening (they may know about the presence of soft markers on ultrasound, but don’t do testing/screening specifically aimed at DS and other chromosomal abnormalities).
@Medvstherapy –
In the United States and many other developed nations, abortion is legal up to 24 weeks regardless of the reason. You can have an abortion because the baby has a defect, or because it is an undesired gender, or because you can’t afford it, etc. Aborting a baby after finding out it has cleft palate or any other defect is just as legal as aborting a “normal” baby for any other reason.
So, arguing that using ultrasound to detect birth defects and soft markers for genetic syndromes might lead to abortions is a moot point. Abortion is legal no matter whether you approve of a woman’s reason for doing it or not. That’s why it’s called a choice.
AlexisT – huh, go figure. Are you a healthcare worker or something? Knowing several people with ultrasound diagnoses of cleft lip and palate would be kinda a strange occurrence otherwise. 1 in 700 children being born with cleft lip and/or palate, it doesn’t come up often with just general social exposure.
Of course, I’ve seen a lot of kids with cleft lip and palate, due to taking my son to his cleft clinic. They seem to have lots of patients and lots of happy parents there.
Regardless, I can’t see withholding important information that responsible parents will find useful to prepare for their child’s care so as to avoid a potential abortion decision. If one is concerned about the abortion fetuses with malformations, parent education, accessibility to needed health care and educational support services are the main fixes in my book.
@d2u: Random tidbit for you – the developmental asymmetries arise early on when the meshenchymal cells migrate through the embryonic plates. They arise because cilia all rotate in the same direction, imparting an angular momentum on the cells as they migrate. This is why in Kartagener’s syndrome there is often situs inversus, because they lack ciliary motility.
It is interesting that a chiropractor, who is forbidden by law in California from practicing obstetrics, deems herself a sufficient “expert” to hold forth on the advisability of an ultrasound during pregnancy. The website cited in her “expert” opinion on ultrasound also contains information on the “Webster Technique,” a bogus chiropractic procedure which purports to turn a breech baby. (In addition to anti-vaccination misinformation.)
@daedalus2u
“Don’t chiropractors like to take full body skeletal x-rays like they are going out of style? Kind of curious that Christine Anderson denigrates the use of ultrasound but endorses and uses x-rays prior to most chiropractic treatment to “treat” what is certainly a non-medical condition, bad subluxations.”
I happen to have a copy of a chiropractic textbook, “Pediatric Chiropractic,” Anrig C, Plaugher G eds, Lippincott Williams & Wilkins (1998), which contains a chapter, “Diagnostic Imaging.” It contains a number of x-rays of infants and children supposedly demonstrating the chiropractic “subluxation” and supports the use of x-rays of pediatric patients to detect the non-existent chiropractic subluxations.
Harriet, I am aware that there was a great stigma against left handed individuals. I remember a case from fifth grade where a student who had terrific handwriting with his left hand and which slanted to the left was failed by his teacher because she wanted it to slant to the right. It was senseless bullying of someone who was left handed.
I found this very interesting paper on symmetry development in frogs.
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3149648/?tool=pubmed
This next paper shows the acoustic waveform (figure 2) that is typically used in prenatal ultrasounds.
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2390856/
It is interesting that the 5.8 MHz pulses are repeated at ~9 Hz. That puts power at a 9 Hz frequency. If that is close to the frequency that disrupts left-right symmetries, that might be the problem. If so, it might be possible to mitigate that problem just by dithering the frequency of repetition or interrupting it so the number of contiguous pulses isn’t that long.
If there is a disruption of left-right symmetry breaking by exposure to ultrasound, it is likely that is is only the left-right symmetries that are being determined at and during the specific time of the ultrasound would be affected.
I suspect (but this is quite speculative), that there are many asymmetry breaking events in utero, and that these