Ultrasound: Powerful, Dangerous, Unethical

by Jean Robinson
AIMS Journal, Winter 1999/2000, Vol 11 No 4
posted with permission

When Dr. Stuart Campbell says he is worried about the way ultrasound is being used on unborn children, we should listen. Hitherto he has been the great apologist and defender - oft quoted in the press as saying it has been used on millions of babies and there is no evidence of harm (a claim which AIMS has strongly disputed, of course.)

However, recently he and Dr. Platt, his co-editor of a specialist journal on ultrasound, were faced with a dilemma. [1] Two studies were submitted on early human embryos, and the most powerful forms of ultrasound - pulsed and colour Doppler - had been used. [2,3] These create intensities many times higher than normal scans. And, as we already know, when the probe is inserted into the vagina, as in this case, the ultrasound does not have to go through the wall of abdomen, which absorbs some of the energy. The journal had previously published studies where pulsed Doppler was used at 11-14 weeks gestation, but when it came down to 10 weeks it seems the editors became concerned.

The editors admit there is "a serious lack of experimental data on the effects on the fetus of colour and pulsed Doppler ultrasound when performed transvaginally in the first trimester." (In fact there is no adequate information on long term effects on the human embryo or fetus of ultrasound exposure via the mother's vagina or of exposure to colour and pulsed Doppler at any stage of pregnancy). And these were being used before 10 weeks gestation when the organs were not even formed. Please note that this was non-therapeutic research - there was no way it was going to benefit the mothers or babies concerned.

Was it ethical for the journal to publish the studies? They consulted their large international editorial board. Two members thought that such research should only be done if the woman was going to have an abortion. A third agreed, but said Doppler could be used if it was of proven clinical value.

But in that case, said the editors, how would doctors be able to find out if early studies could predict later problems in pregnancy? (Not that there is any early treatment for such problems, of course, even if they can be predicted, and the track record for benefits of later ultrasound is poor, as our readers know.)

The editors have therefore evolved an "ethical policy" for future publication. It includes "informed patient consent" - and the patient information sheet is to be submitted to the journal. May we suggest they actually publish the information so we can all see it? Since there is, at the moment no information on what happens to children exposed as tiny embryos to the most powerful forms of diagnostic ultrasound, it will be intriguing to see what women are to be told.

It is far from reassuring to see a piece in the same issue by Chervenak (one of the editorial board) and McCullough, both ultrasound experts, simply saying "Pregnant women should be assured that only appropriate power levels will be used in fetal Doppler ultrasound studies. They should also be informed that there are no documented risks to the fetus at such power levels, that the research may benefit her fetus or her." [4] Appropriate for what and for whom? As a veteran member of three research ethics committees, I don't know whether to be surprised at their ignorance or amazed at their effrontery.

The research must be also approved by an ethics committee, say the editors. But that is standard procedure in any reputable medical journal anyway. The two studies they published were approved by local ethics committees in Finland and Philadelphia, whose members now have egg on their faces. In future the information provided to the ethics committee on safety must also be submitted to the journal So how come they did not ask for all this information before publishing the two studies? We suggest they publish that information too, especially since the consumer interpretation of risk often differs from Professor Campbell's. [5]

Their future policy also includes insisting that the equipment must display the safety limits for the thermal index (TI) - how much the tissue may be heated - and the mechanical index (MI) - which refers to the force which can cause gas bubbles to be formed, stream and possibly damage tissue - and might show effects of radiation pressure. The embryo is submitted to a forward force every time a pulse passes through it. As medical physicist Dr. Frances Duck points out, diagnostic Doppler ultrasound causes higher exposure than normal scans, and can heat soft tissue. [4] (From many human and animal studies we know that raised temperatures can cause abnormalities.)

In fact the TI is already known to be inadequate, because it does not estimate what happens to the tissues near the transducer. When ultrasound equipment is used in the oesophogaus, the transducers have a cut-out mechanism if they become too warm. Vaginal probes do not.

Frances Duck had already warned that the revised standards allowed since by the FDA since the early 1990s do not prevent the sale of excessively powerful machines.[6] And now we don't even know how powerful they are. The ultrasound power is measured by the waves it creates in water. After a certain point the water becomes saturated so higher power is simply not measurable by this method.

The future ethical code of the journal also insists that exposure times must be based on the ALARA principle (As Low as Reasonably Achievable) and that exposure times must be given. We do not find this reassuring. A radiographer would use the least and shortest exposure to X-ray a fetus - but we don't X-ray the fetus at all unless it is absolutely necessary. Please note there was no unexposed control group in either study, and no plans are mentioned for follow up of the children.

What we find surprising is that neither study tells us how many of the babies were born alive, and in what condition.

48 women were studied in America; 60% of them had had ovulation induced. They had ultrasounds at 4-5 weeks, and then every two weeks until 13-14 weeks. Ten pregnancies miscarried before 13 weeks, having been involved in 27 studies, and the remaining 38 women had 145 examinations. We are told the surviving 38 pregnancies "progressed to term without any significant fetal complication or anomaly detected." For all we know the babies could be dead, but "normal." How odd that the editors did not require more detailed final data from such a meticulous study of the earliest fetal heartbeats. The authors show that the babies which miscarried were less likely to show early heart valve activity. Were these pregnancies destined to end, or were they the babies more vulnerable to ultrasound?

In the study from Ouolu, Finland, researchers looked at the development of the yolk sac in 16 women who had examinations at 5, 7, 8 and 10 weeks. They started with 20 but four were excluded because two pregnancies were outside the uterus, one was anembryonic and one was aneuploid. (We are not told at what stage the missing embryo or chromosome abnormality were detected.) The only information we get on outcome in the rest is "The course and the outcome of all pregnancies were uncomplicated." So - did they go to term, what were their Apgar scores, did they spend time in intensive care, were they born alive, are they still alive? After providing us with copious information about blood flow in yolk sacs, surely the authors could spare a sentence to tell us what happened to the babies, and it is surprising the journal did not require it.

There is no doubt that these studies can come up with interesting scientific information. The question is, what price will some mothers and babies be paying to provide it - and how shall we ever know, when it's only the powerless consumers who want to find out?

It is significant that one of the studies was done on women who had had fertility treatment. It is on this group that transvaginal probes and ultrasonic study of embryos began - these women were only too willing to agree to investigations they thought might help and give them early indication of pregnancy. Is it coincidence that outcome of such pregnancies - the most closely monitored of all - is so poor, with a high rate of both abnormalities and deaths?


[1] Campbell S, Platt L. The publishing of papers on first-trimester Doppler, Ultrasound Obstet Gynecol, 1999: 14: 159-60

[2] Leiva M C et al. Fetal cardiac development and hemodynamics in the first trimester, Ultrasound Obstet Gynecol, 1999; 14: 169-74

[3] Makikallio K et al. Yolk sac and umbilicoplacental hemodynamics during early human embryonic development, Ultrasound Obstet Gynecol, 1999; 14: 175-9

[4] Chervenak F, McCullough L, Research on the fetus using Doppler ultrasound in the first trimester: guiding ethical considerations, Ultrasound Obstet Gynecol, 1999; 14: 161

[5] Beech B, Robinson J Ultrasound? Unsound, AIMS 1996

[6] Duck F, Is it safe to use diagnostic ultrasound during the first trimester?, Ultrasound Obstet Gynecol 1999; 13: 385-8

Beverley Lawrence Beech's "Ultrasound - weighing the propaganda against the facts" in AIMS Journal Vol 11 No 4

AIMS makes information and articles freely available on its website as a public service. They also provide advice and support to individual parents and professionals at no charge. If AIMS has helped you, you can help them to help others by joining or making a donation.

Additional Ultrasound Research Linked at:
Ultrasound, Doppler, Fetoscope & Pinard Horns



  1. I was having complications early on in my pregnancy with my second pregnancy, my dd, and as such had a couple vaginal u/s because the dr said it was necessary...starting at 10 wks. i didn't really feel so. I figured if God wanted me to have this baby everything would be fine. In my gut I knew everything was fine. I had several u/s with her because they were worried about her. When she was born she wasn't breathing and it took them a little over 5 min to get her to breathe. I almost lost her. In the mean time I hemorrhaged real bad and they had blood waiting for me. Idk if any of that had to do with the multiple u/s however with my ds I only had one u/s with him at 23 wks and there were really no complications with him. He was wheezing when he was born but they never could explain that to me. Both were natural births.

    I personally feel that being so invasive actually can hurt everyone involved. These machines were made to detect enemy ships not check on a baby every step of the way. Who knows how it is altering our chemical make up, let alone our children and future generations. There is so much to be said about everyday appliances that just came about not even a century ago and we may just now be seeing affects of them passed on by our parents to us through mutated genetics.

    I wish that people would understand that the 3d/4d ones are even worse for your poor kid and let well enough alone. People have been having kids for thousands of years without all this stuff. Why do we need it now?

    Sorry so long. I feel that the u/s did play a factor in my dd's delivery and complications.

  2. I've just met a family who had twins two years ago. They went for an ultrasound on the twins at 24 weeks and during the u/sound exam, the mother felt a "shock". While the transducer was on her belly, the technician said "One of your baby's hearts has just stopped beating". It was beating when the exam started and the mother believes she got an electric shock and it killed one of her twins.

  3. I definitely believe that fetal ultrasound is overused. There are many women in normal (low) risk pregnancies who have scans at almost every prenatal visit and are happy about it, since they get to see their babies again. While I personally didn't worry excessively about the risk of having a single 20 week scan for anomalies and placentation based on my age and pursuit of a VBAC, I do get very nervous about additional scans and would not have them done barring some specific and important medical concern. I can live without seeing my baby every week or month. And those "4D" boutiques are even freakier to me.

  4. With my first I just had several scans. However, no vaginal. A dating scan at 6 weeks, where shortly after I started bleeding (although the same happened with my second and no US was involved that time, under scientific standards I would say that a US could have been the cause of the bleeding but it was likely the loss of a twin which is more common), I had a second US at 7 weeks and was told I'd miscarried, I had one at 8 weeks before my D&C and was told I was still pregnant (normal procedure), I had a Nucal fold scan at 12 weeks as genetic abnormalities run in my family. I have two siblings with Downs, and my other sibling died of Edwards so I was at high risk of having a child with a problem. In the end she had Poland-mobeius Syndrome. I had a further scan at 20 weeks to check growth. Then no others, even though my eldest remained breech until she was 36+5weeks. She was born with complications, but because I was considered "low risk" and with a prolapsed cord, early breaking of waters, and pitocin, made my delivery extremely dangerous. My child nearly died. While it was the medical profession that nearly killed her, it wasn't the US's that caused the problem.

    With my youngest I had many more. Mainly because I bled on and off through-out my pregnancy and had a low seated placenta. It felt very invasive though. In any future pregnancies, I will only accept a maximum of 3 scans (12/20/any 2nd or 3rd tri major bleed). However, despite having so many more scans with my youngest, she popped out and was 100% with no issues. She is considered gifted. Whereas my eldest is less so, with various issues including dyslexia, dyspraxia, speech problems, hearing loss and flat feet. Tbh that's the only difference yet the youngest had more US than the eldest. However, the youngest had a US at an earlier gestational stage. Personally I attribute her problems to be specifically to do with the interruption of blood flow during her 6/7th week.

    Fetal US is over used. I was refused treatment if I didn't have a US after I tried to refuse one with the second. I was bleeding, and afraid that I would loose the baby so I capitulated. However, I am much stronger now, and wouldn't let it happen again.

  5. So is this talking about the ultrasound equipment or also the doppler used to listen to the heartbeat?

  6. Interesting. I had numerous ultrasounds as I had two sets of identicle (but each had their own amniotic sac) twins. All but 1 ultrasound were in the 2nd and 3 trimester and the vast majority were in the last 3 weeks of pregnancy. None of my kids had any complications at or before birth (or post birth for that matter!)

    What is interesting to me, is that babies concieved via IVF have a host of increased risks - like that of developing childhood cancers. And the cuase of this is unknown. Combine that with the knowledge that nearly every IVF case (in the U.S. - not sure elsewhere) has a 3-4 week ultrasound and averages more followup ultrasounds and there may be a theory to be tested...


    Tandem Twinning

  7. Thank you for this. It has made me rethink getting a 9-10 week "viability and dating scan". I had one with each of my girls. With the first, it was abdominal and the second it was transvaginal. My younger daughter has several allergies and eczema and I wonder if the ultrasounds contributed.

    I had way more ultrasounds with my first, but all were abdominal and most were in the third trimester. I think for future babies I will skip the early ultrasounds and only opt for the 20 week and then anything after that as needed.

  8. I think that mothers place to much value in seeing their child pre birth, and do not stop to relies at what cost they may be paying for the ability. I know of so many families getting scanned at every appointment as a precaution, but no one knows what they are being cautions about?! I think that so many scans also undermine the woman's ability to trust her body because every appointment, or every other appointment we need to use this machine to make sure your baby is healthy in there, and that totally leads to believing that her body is not capable of doing this safely on its own... it must be checked and monitored and observed, and tested or something may go wrong and the professionals would not know about it. What kind of message do we want to be sending mothers? one of fear? or one of empowering? Start by allowing a mother to trust her body and stop trying to see every aspect, trust that she will know when things are off and ask about it.
    ... sorry off my soap box now!

  9. As a high risk pregnancy I do have a lot of scans, I think it is usually around 30 (I always lose count) but this one has been quite quiet at just fortnightly. They are important scans and before they knew how my body works I lost a baby mid-T to a natural labour and they were caught out by my next one going into a rapid premature labour. If I was to put my trust solely in God I would lose my babies, I say that as a Christian who believes God can do all things but I also believe He has given us the ability to do somethings ourselves.

    Like any intervention though it should be used when needed, even if that's a lot of use like me, and not just made routine.

    Something a lot of people don't realise though is the sonicaid (the handheld Doppler) uses more ultrasound than an ultrasound.

  10. It hurts my head to read these mindless comments. Ultrasound has been shown to interfere with neuron migration, it is positively correlated with miscarriage, it is a physical displacement of matter and there is a conflict of interest on the part of doctors who don't want to tell people that their ca$h cow is nothing short of a brutal and savage shaking of the unborn child, vicious child abuse.



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