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Is Ultrasound Scanning During Pregnancy Worth the Risks?

While ultrasound scanning doesn't pose the same dangers to human and fetal health as ionizing radiation, it is a mistake to think that ultrasound is entirely safe for a baby growing in your womb.

Ultrasound scanning works by sending sound waves into your tissues. As these sound waves bounce off of your tissues, a picture is created.

These sound waves are capable of producing the following physiological effects:

  • Increase in blood flow and temperature in local tissues
  • Production of gas bubbles that can put pressure on local tissues
  • Mechanical effects like movement of the fluid that surrounds your cells, which can also put pressure on local tissues

The conventional view on ultrasound scanning during pregnancy is that the intensity and duration of sound waves that are used for scanning are not enough to produce these physiological effects at a level that is harmful to a fetus.

I believe that this conventional view is influenced by the number of dollars that are being made by this industry.

Before you allow ultrasound scanning to be performed during pregnancy, please consider the following points:

  1. Ultrasound scanning of pregnant women has been shown to significantly increase the likelihood of miscarriage, preterm labour, and even infant mortality.
  2. Pregnant physiotherapists who provided ultrasound treatments for more than 20 hours per week were found to have an increased risk for spontaneous abortions.
  3. One of the reasons used to support ultrasound scanning for pregnant women is that it can help to diagnose a condition called placental praevia. This is a condition where the placenta is implanted in the lower part of a woman's uterus, which can cause bleeding in the third trimester and increase her chance of being encouraged to have a caesarean section. A study of 4000 women found that of 250 women who were scanned and diagnosed with placental praevia, only 4 actually had placental praevia upon delivery. Who knows how many unnecessary caesareans have been done and how much needless anxiety women have experienced due to incorrect diagnoses of placental praevia wiith ultrasound?
  4. Using ultrasound scanning to detect serious problems before birth does not necessarily save lives or reduce illness. There is evidence to suggest that using ultrasound to attempt to detect problems while a baby is in the womb can do more harm than good.
  5. There is evidence to support that children who have been exposed to ultrasound while in their mothers' bellies have a greater chance of suffering from dyslexia and other speech and learning problems than children who have not been exposed to ultrasound.

Ultimately, the two main reasons why I believe that it is best to avoid ultrasound scanning during pregnancy are:

  1. No matter what intensity and duration of ultrasound waves are used, there is always a possibility of these waves creating unnecessary thermal and physical pressure to a growing baby. Why take this risk?
  2. There is always a possibility of practitioner error and/or a defective machine that can result in a higher than intended dose of ultrasonic waves to your baby.

For more information on why you should think twice before having ultrasound scanning done while pregnant, please read: Ultrasound? Unsound, by Beverley Beech. Copies are available from AIMS.


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Thank you for your article on the concerns regarding ultrasound. It is hard to find anyone who questions the use of this device for pregnancy. I am currently 26 weeks pregnant with my fourth child and have not had an ultrasound in over 4 years! Unless my health throws into question the health of the baby I have no intentions of ever having another pregnancy ultrasound. My first experience with ultrasound was to detect gestational age of my first son at approximately 6 weeks pregnant. The next routine ultrasound done discovered that my cervix is shorter than average, about half as long as most womens. I went to a specialist and had more ultrasounds. It was recommended to me and my husband that we abort the baby to prevent premature birth, death of the baby or life long health problems. We were appalled at the suggestion! And more over confused about their reasoning. They were concerned that my cervix would not hold the weight of the growing fetus. If we had gone through with their suggestion it could have damaged my already short cervix and prevented me from ever experiencing a full term pregnancy. As it turns out my son was born 2 weeks early at 7lbs 12oz totally healthy! He will be turning 5 this year! He is really smart and funny unfortunately though he is showing signs of dyslexia, however minor they may be I can't help but wonder if all those scans affected his mental development. Not to mention my original questioning of the procedure. I decided not to have ultrasounds with my following pregnancies because of the reaction of the fetus. I always found it odd that a harmless procedure would cause the fetus to 'run' from it. The fetus always acted fearful, the heart rate would go up and the fetus would move away from the wand. For us that was enough for me to never have another scan done. Fear alone can cause health problems and I didn't want to see my baby in fear for my entertainment. I am now wondering if I should be concerned about the routine use of dopplers?

I too was advised to terminate my pregnancy because of a scan. At 6 months the scan showed fluid on the lungs and abdomen and I was told my baby would not be able to breathe once born. The specialist who I was booked to see was away at the time so my appointment was in 2 weeks. So the termination had to wait. Two weeks later much to the astonishment of the specialist the next scan showed the fluid gone but the baby had swelling of the liver suggesting their had been an infection. Around that time the baby did not grow. I refused any more scans and went on to fullterm delivering a healthy, small (51b 80z) baby. She has been well other than in her teenage years she had some bouts of nephrotic syndrome (her kidney leaked protien causing swelling), I don't know if this was related or not. She hasn't had any flareups for a long time and is now 24 years old. I would never have another scan with any pregnancy, there are too many unanswered questions and medical staff too quick too find problems - not really knowing what the future will hold.

I am quite in agreement with the thoughts in this article on a theoretical level.

But I want to share my personal experience which is an exception (perhaps rare).

My first pregnancy was discovered to be a twin pregnancy--discovered by ultrasound at 9 weeks. At my 18 week screening ultrasound, we were diagnosed with Twin to Twin Transfusion Syndrome which needed almost immediate (later that week)laser surgery. One boy was getting to much blood and could have gone into heart failure, and the other one was literally "shrink-wrapped" in his sack. His bladder was also not visible (from lack of nutrition/fluid). Overnight, even I as an un-trained ultrasound reader, could see the very obvious difference after the surgery. The smaller twin finally had fluid in his sack and could move and had a visible bladder....and the other boy's fluid amounts reduced to normal.

These screening ultrasounds saved my boys' lives...At very least IF either one had survived without this immediate treatment, they would have likely been handicapped (based on what often happens in this condition). They are both now healthy, intelligent wonderful boys, and I couldn't imagine life without them.

I don't honestly know if there may have been some negative effects from the ultrasounds they's hard to say. But it did save their lives. I don't think the twin pregnancy and their perilous condition would have been discovered in time otherwise.

I don't like to be a nay-sayer, because I so agree with this article...but because of my personal experience with a real situation, I want to say it's not always so simple. People should certainly be willing to have an ultrasound if they have a sense of needing to do that. I know the chances are pretty low...but for us, it was my boys' lives....

Thank you so much for standing for unpopular views, Dr. Kim. I hope I don't sound like I'm opposing you...I so appreciate all your work! I just felt compelled to share...

I do agree that there may be exceptions if you are high risk, like if you are having twins or multiples, but if you are having a relatively normal pregnancy, I don't think it's necessary to have so many ultrasounds. I do think it disturbs what is happening there organically, and there haven't been enough tests/studies done to prove that sound waves are indeed not harmful on babies. There have even been some studies showing that more ultrasounds caused male babies to be born left-handed as opposed to right-handed. I do think that so many ultrasounds are unnecessary and I think maybe 2 max would be beneficial. One to date the pregnancy and the second one when you are 20 weeks or so to find out the gender and look at the anatomy. I heard of some women getting 6-7 ultrasounds throughout their pregnancy!

The thing is... how would you know if you are having multiples, let alone the type at risk for TTTS, if you declined a routine early ultrasound? I agree that having a ton of ultrasounds is completely unnecessary, and puts you at more risk for finding false positives (adding stress, which *can* be harmful), but I don't think there's any real evidence that a couple routine ultrasounds has any negative effects. I mean, I'm not going to use a Doppler every day (and I know some women who do), but these kinds of articles get people freaked out about a 10 minute scan that could be really beneficial.

Frankly, I would really like to see some citations for these facts... the most recent review I have found on the subject suggests that these risks are minimal at best, and bogus at worst:

Well said Jackie. The tone of the article was very definitive and spoke with authority about 'evidence' yet provided absolutely no details of the quality of the research providing this supposed evidence base. The bottom line is that in the UK the NICE (National Institute of Clinical Excellence) conducts annual systematic reviews of the evidence base for all medical interventions carried out by the NHS. The NHS would not be delivering 12 week dating scans and 20 week screening scans if there was
any solid evidence base that suggested that the risks outweighed the benefits.

I too would like to see the scientific and scholarly articles supporting Dr. Kim's assertions. My sister in law is buying into this anti-conventional opportunistic crap and it scares me for my brother's baby. I would rest a little easier if Dr. Kim could point me to at least 5 reputable licensed OB/GYNs who are willing to back up these assertions on this website. What other effective methods are out there to detect birth defects or placenta previa? I have two beautiful, healthy children and can't imagine purposely denying them or my wife and I every opportunity to detect and deal with potential birth defects or maternal health risks. Dr. Kim, please PROVE to me why I don't need to be concerned about my sister in law's rejection of modern medicine's benefits. Because it's all about large corporations brainwashing us? Seriously? That shows very little faith in humanity. And is inherently hypocritical. Who's trying to scare who here?

(To the mom who wonders if her child's dyslexia is due to ultrasounds: where would you come up with that wild idea? What possible theory correlates the two? Just sounds ridiculous to me. Please explain to me how you became convinced that ultrasounds do more harm than good. How did you get there?)

- concerned brother/uncle

Ive been really worried about my partner who is 41 weeks pregnant. It is not her first child and my two children had ultrasound scans - more than usual. The thing is she has asked for more scans as she is epileptic, her daughter had athrogryposis and she is suffering with SPD and irritable uterus. The Hospital appear to not be interested and she is considering going to another hospital to give birth. She is worried - she hasn't been able to move for 8 weeks and there has been no duty of care.

An ultrasound scan would have put her mind at ease and I know that hospitals set their own costs for this service - why does it cost so much at some hospitals? and why are hospitals so reluctant to help or advise. I have seen a solicitor as I am extremely worried with my pertners history and the hospitals lack of duty of care (negligence)

I had an ultrasound at 8 weeks ( not knowing any better ) with my first child and he is dyslexic and suffered at school and still does to this day.I think it is much safer to wait until 12 weeks if you have to have an ultrasound as at least then the babys organs are all fully formed and perhaps the risk is not as great.I do not think the other lady who mentioned this is silly at all..If i could have changed what i did and had a child without dyslexia i certainly would not have had that Ultrasound.

I agre with the previous posters, where are the (peer-reviewed) articles providing the basis for these statements. Further, where lies the balance of the literature. I'm also not happy with the use of the word 'significant', for a scientist it means something that's different enough from the mean, given the variance of the observations. Hence something that is 'significant' can also be miniscule in size. Non-scientists reading this will likely misunderstand 'significant' to mean large, which is not necessarily (and I tihnk in this case very likely not) true.

Here is an article with 13 references: More research has been done since that article was published.
The study "Prenatal Exposure to Ultrasound Waves Impacts Neuronal Migration in mice" was published in the Aug. 2006 Proceedings of the National Academy of Sciences. Funds are very limited for studies such as these because there is no monetary return for the money spent! Ultrasound seems to have holy grail status now (as Dr. Kim mildly hinted) so to be a whistleblower not only means to spend money w/ no return, but possibly make enemies as well.

Excellent citation. For all those questioning the claims in this post I urge you to read through the findings provided in the link.

Concerned brother/uncle

I am a new medical student, but in our very first class you are taught the doing ultrasounds, which produce sound waves, give off radiation. The radiations contacts the fetus and has the capabilities to alter cellular chemical reactions. It can make a cell mutate and therefore set your child up for problems.

Like I said I am not a doctor...yet, but that is the concern with ultra sounds.

I had ultra sounds with all 3 of my children, very few with my first and second. Due to a health complication of mine, our third child endured many ultrasounds, God be the glory that between those and all the meds they had me on, he seems to be developing normally! There are many cases we will never know as molecular structures that have mutated or been killed off usually are not discovered until later in life.

I think all decisions have to be made with much prayer.

Ultrasound heats liquids to the point of cavitation/ bubbling (please google this). Military submarines are required to turn off their ultrasound systems around divers and even giant whales because it is lethal. Why is it such a wild idea, then, to wonder if, even at lower levels, it is harmful to have it aimed at a developing fetal brain?

Did you know that wifi waves and microwaves are exactly the same thing: 2.4 GHz electromagnetic waves. However, just because I can cook my food with microwaves doesn't mean that I should be worried about my wifi modem cooking myself. It's all about intensity.

Umm... it has been proven just not by western studies.

Check out the book "50 Human Studies, in Utero, Conducted in Modern China, Indicate Extreme Risk for Prenatal Ultrasound: A New Bibliography" by Jim West.

And please share this book when you're done reading it ((you will read it won't you? Of course you will, you strike me as the type to roll with cold hard fact and not blindly believe everything our western "authorities" proclaim without doing in depth research of your own backed by intelligent critical thinking)) with your sister so the next time she gets looked down on for being accurately informed and up to date on her medical knowledge, she can correct the ignorance with the hard facts supporting her belief instead of just "knowing" the information. As for your nephew... sounds like his mother is pretty on her game, you should be grateful she cares so much about her son and doesn't automatically buy into every misguided sheepish belief she hears! (Such as that our government is impervious to any human corruption whatsoever or that no one in any positions of law making or authoritative power would EVER skew facts or justice for bribes of insane dollar amounts [in fact that's never been done in history at all!!! Right???? Cause everyone really genuinely cares about the well being and health of every other person they're not related to right???])


The sad thing is you ask for proof but is there proof or studies saying it is safe? I have looked and there is not! There is a lot of studies done on fruit fly larvae and mice embryo but nothing to study one way or the other it is safe! In the 1950's they did x rays on pregnant mothers and laughed at the doctors who started to suggest this could be harmful! How could you think that anything medical profession says is 100% safe. Most is allowed based on acceptable losses. But in dealing with a baby just starting off and exposing just because it's routine, is not smart. Parents should go with how they feel about it, but something that is used to explode kidney stones and kill cancer cells obviously has some effects!

I'm studying to become a Vascular Sonographer. I might cross-train and become General/OBGYN (but that's all in the future). I don't know if US affects baby's in the womb, and I assume that the doctor has some reliable sources, however as I study in this program I get Vascular Ultrasound done on me two days a week, occasionally more. If the technologist keeps the Output Power As Low As Reasonably Achievable (Which is how it suppose to be) there shouldn't be any significant tissue heating that could harm a person. Again, if you keep the transducer (especially on high Output Power) for hours on the skin, then yes, there will be tissue heating. But again, I'm not saying that it doesn't or does affect the baby. But I truly do not believe that a 45 minute ultrasound exam twice a pregnancy will harm the child. I think pollution, second hand smoking, and contraceptives (that have been previously used), heredity and other unknown factors could cause all those things that the article and other people listed. Again, I'm not saying that it does or doesn't for sure. But saying that Ultrasound Causes all of it, without providing any 100% proof could be a bit doubtful.

Sadly, women have long been decreasing their level of active participation in the knowledge health of their bodies. Before scans were available, many women was knowledgeable of carrying twins, therefore it seems that we have become too reliant on others to tell us our status.

Palpating frequently has been used for forever. Women can palpate to know if there are mutliples. I know it doesn't tell all, but it has worked in the past by midwives.

My point simply is that there qre ways to know. Slowing down to become intuned with yourself, palpation, uterine size, and fetoscopes aid in figuring things out in most cases it seems.

Yet, it does seem to be a blessing to monitor things when truly abnormal situations happen.

Sadly, women have long been decreasing in their level of active participation in the knowledge and health of their bodies and babies. Before scans were available, many women was knowledgeable of whether they were carrying multiples. Thus, it seems that women in general have become much too reliant on others to tell them their health status.

Palpating frequently has been used for forever. Women can palpate to know if there are mutliples. I know it doesn't tell all, but it has worked in the past by midwives.

My point simply is that there are ways to know. Slowing down to become intuned with oneself, using palpation, measuring your uterine size, and a fetoscope can aid in figuring things out in most cases it seems. Technology has become the new human, and is often incorrect.

Yet, it does seem to be a blessing to monitor things when truly abnormal situations happen.

I am an ultrasound technician and this is absolutely ridiculous! Ultrasounds cause boys to born left handed instead of right? Are you hearing yourself? I recommend doing testing that your doctor advises. Plenty of women have had ultrasounds during pregnancy for years now! I think they would know if it was unsafe?

Are you referring to dyslexia?
That is NOT being left handed. It is not being able to read because you reverse letters, words, and numbers.

Concurrent with the increased use of ultrasound is a dramatic rise in autism rates. Of course it would be only one contributing factor among many, but it is worth a look. Prenatal ultrasound has been "presumed safe til proven harmful", when it should be the other way around.

Thanks to an ultrasound I am still alive and able to care for my children. I was diagnosed with placenta previa. Had I not had several ultrasounds, I could have delivered vaginally only to bleed to death. Thanks to the ultrasound technology I am able to see my child grow. She is now 5 years old. Way ahead of her class. Speech developed extremely early and with amazing clarity (speaking like a 5 year old at age 3). Her writing is very advanced, and she is fluent in two lenguages and working on a third one. Also very developed drawing skills (drawing stick figures with many details at the end of age 2.) My point is: I had more than the average ultrasounds, and my daughter is extremely smart. No developmental problems whatsoever. And, I am still alive to see all that! Thank God for ultrasounds.

I began spotting at the beginning of my 29th week and was told to ignore it. The next morning I almost bled to death. Fortunately, the placenta previa was found during an ultrasound and I was put in intensive care. I stayed there, with medication for me and for my unborn son, four weeks before my son was delivered via C-section. I bled several times, and received transfusions during the delivery. My son was born able to breathe on his own thanks to that ultrasound. And I didn't bleed to death. Both good things.

I do not advocate unnecessary C-sections. But if one case of actual placenta previa is caught and one maternal death is avoided, or stillbirth, because of ultrasounds then much good has been done.

I think that more than 1 ultrasound during pregnancy is unnecessary but I really can't see how it causes dyslexia. My son was diagnosed with dyslexia and a learning disorder and I think it was caused 100% from the vaccinations. I had 3 ultrasounds with him but there are others that have more and their children are fine. I think that people should be more concerned with what's being pumped into their bodies with unnecessary vaccinations. My daughter has no vaccinations and is above average in learning. I also had 2 ultrasounds with her.

with my first pregnancy I didn't really tell anyone I was pregnant until I showed, I delivered a healthy baby boy that weighed 7lbs. but that's the reason why I had the social service after me just before he was born, cause I didn't tell them about the pregnancy until I was 6 months... my son is extremely smart and talkative, and very articulate, he's been speaking and using full clear English, and long sentences since 2 years of age maybe cause I didn't have any scans apart from one in the very late stages of pregnancy. I feel having an ultrasound scan can affect the baby's health and mentality. a lot of the women I know who had them, their children suffer from dyslexia and learning disabilities which is pretty sad.

during this pregnancy I've only had one scan at 20 weeks and the lady said that the baby's fine. She didn't tell me the baby's gender or anything else that I wanted to know. she said if I'm having an abortion I wont need to know and if I want to carry on with this pregnancy then I have to get a detail scan done... The next day I receive a call from the hospital saying to come in the following day to get a detail scan. is it too close apart, my scans. cause a lot of women have their next scans after two three months. I am kind of worried this could affect my baby's health and learning, should I not go and give this as a reason to them

As a challenge to conventional belief, ultrasound is clearly shown to be very damaging to the human fetus, via my <cite><strong>Bibliography of Human Studies</strong></cite>, modern, high-tech studies. See

THANK YOU for curating and presenting this info! Any chemist knows that ultrasound causes liquid temperatures to rise to the extent of cavitation (bubbling) so why would we want to risk hyperthermia in an embryo or fetus, which is 70% water and floating in an aqueous environment? Military submarines are required to turn off their sonar in the presence of whales and divers because it's lethal. Obviously that's much more intense than fetal ultrasound machines, but in the absence of definitive demonstration of safety, fetal ultrasound should be reserved for cases of medical necessity only.

This article makes claims that may sound terrifying to an expectant parent, but it references no information to supports its claims. These are the opinions of a “Dr.” (notice the author has no actual degree listed). Anyone claiming to give advice should be transparent about where they get their information, and what their background and training are. This article is total nonsense.

I have pregnancy of 21weeks and rate of ultrasound examine os 12...due to some problems in start of pregnancy..14 ultarsound scan include 1 TVS and - Anomely Scan...
Now i m worried is it safe for baby or may i have to safe side for further ultrasound???
Please inform me...

This page demonstrates an opinion in a blog and appears to be fear-mongering. A better source of medical facts should be found on your local government health websites. Ultrasound has been proven time and again to be a safe and effective way to diagnose problems with fetus, mother and non-pregnant patients and is highly regulated in developed countries. Cancers, lost limbs, twins, heart defects and facial abnormalities are just a few of the issues your sonographer is trained to look for. Please confirm with your doctor or sonographer whether ultrasound will provide benefit in your pregnancy.