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Natural Childbirth IIb: Ultrasound Not as Safe as Commonly Thought


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In the last article in this series on natural childbirth, I reviewed evidence suggesting that routine prenatal ultrasound does not improve birth outcomes for mothers or babies, and that organizations like the American College of Obstetricians & Gynecologists recommend ultrasound scans only for specific reasons.

In this article I’m going to review evidence on the safety of routine ultrasound and Doppler scanning, and make recommendations based on that research.

The potential adverse effects of ultrasound

According to Australian family physician Dr. Sarah Buckley, MD in her book Gentle Birth, Gentle Mothering, ultrasound adversely affects body tissues in three primary ways:

  • Heat
  • Cavitation
  • Acoustic streaming


The sonar beam can cause heating in the tissues beings scanned. During normal pregnancy, increases in whole-body temperature of up to 4.5 degrees F (2.5 C) are presumed to be safe, and research suggests that elevations of tissue temperature up to 1.8 – 2.7 degrees F (1.0 to 1.5 C) caused by ultrasound are also safe.

The degree to which ultrasound machines raise temperatures in the tissues depend on which tissues are scanned. Bone heats more than soft tissue, which in turn heats more than fluid. Heating is also dependent upon exposure time, the intensity of the machine, and whether the transducer is held stationary or moved frequently.

Doppler ultrasound, which uses continuous rather than pulsed waves, has been shown to cause significant heating – especially in the baby’s developing brain. A recent study suggests that heating in late-pregnancy fetal tissues exposed to normal pulsed and continuous Doppler ultrasound may be higher than what is regarded as safe: 2.5 to 10.4 degrees F (1.4 – 5.8 C) respectively.

A 1997 study found that significant temperature increases can occur at or near to bone in the fetus starting in the second trimester, if the beam is held stationary for more than 30 seconds in some pulsed Doppler applications. This in turn can lead to heating of sensory organs incased in bone.

Though both animal and human studies have shown that temperature elevations can cause abnormal development and birth defects, so far human studies have not shown a direct causal relationship between diagnostic ultrasound exposure during pregnancy and adverse effects to the developing baby.

However, it must be pointed out that all human epidemiological studies were conducted with commercially available devices predating 1992, with acoustic outputs not exceeding an intensity of 94 mW/cm2.

Current limits in the U.S. have risen dramatically, and now allow intensities of up to 720 mW/cm2 – more than 7 times the limit in 1992. This means we have no large, population-based studies examining the effects of ultrasound at the much higher intensities commonly used today.

This is highly problematic, because, according to a 2001 review called “Guidelines and Recommendations for Safe Use of Doppler Ultrasound in Perinatal Applications“:

When modern sophisticated equipment is used at maximum operating settings for Doppler examinations, the acoustic outputs are sufficient to produce obvious biological effects, e.g. significant temperature increase in tissue or visible motion of particles due to radiation pressure streaming effects. The risk of inducing thermal effects is greater in the second and third trimesters, when fetal bone is intercepted by the ultrasound beam and significant temperature increase can occur in the fetal brain.

A 2007 study reached a similar conclusion:

(1) thermal rather than nonthermal mechanisms are more likely to induce adverse effects in utero, and (2) while the probability of an adverse thermal event is usually small, under some conditions it can be disturbingly high.


Cavitation occurs in tissues with significant pockets of gas (such as the lung and the intestine) after birth. There is no consensus on the significance of cavitation effects in human fetal tissue, but some evidence suggests that mammalian tissue may contain microbubbles that are susceptible to cavitation effects.

Acoustic streaming

Acoustic streaming involves a jet of fluid created by the ultrasound wave, which causes a mechanical shearing force at the cell surface. While the effect of this force is not fully understood, research suggests that it may change cell permeability and have adverse effects on both early and late prenatal and postnatal development.

Animal studies suggest diagnostic levels of ultrasound may cause harm

One study found brain hemorrhages in mouse pups exposed in the womb to pulsed ultrasound at doses similar to those used on human babies.

Another study found exposing adult mice to dosages typical of obstetric ultrasound caused a 22 percent reduction in rate of cell division and a doubling of the rate of apoptosis of cells in small intestine.

Other research has found that ultrasound induces bleeding in the lungs among other mammals, including newborns and young animals.

The American Institute of Ultrasound in Medicine concluded:

There exists abundant peer-reviewed published scientific research that clearly and convincingly documents that ultrasound at commercial diagnostic levels can produce lung damage and focal haemorrhage in a variety of mammalian species…. The degree to which this is a clinically significant problem in humans is not known.

I want to be clear: we can’t extrapolate the results of these animal studies to humans, and so far, many longer-term human studies have not shown harm to the fetus from diagnostic ultrasound exposure. However, when the stakes are this high (i.e. the health of our children), I believe the animal study results warrant caution and further study before plowing ahead with ultrasound technology.

Some human studies also suggest harm…

Single or small studies on humans exposed to ultrasound have shown that possible adverse effects include premature ovulation, preterm labor or miscarriage, low birth weight, poorer condition at birth, perinatal death, dyslexia, delayed speech development, and less right-handedness.1

This is especially true for Doppler ultrasound, which is used in specialized scans, fetal monitors and handheld fetal stethoscopes (sonicaids). Ordinary scans use pulses of ultrasound that last only a fraction of a second. The machine uses the interval between pulses to interpret the echo returns. Doppler, on the other hand, uses continuous waves – leading to much higher levels of exposure than with pulsed ultrasound.

A large UK study found that healthy mothers and babies that received two or more Doppler scans to check the placenta had more than 2 times the risk of perinatal death compared to babies unexposed to Doppler.

An Australian study found babies that received more than 5 Dopplers were 30% more likely than babies that received routine (pulsed) ultrasound to develop intrauterine growth retardation (IUGR). This is ironic because Doppler is often used specifically to detect IUGR.

A randomized clinical trial published in 1996 split 2,743 women into two groups: one that received a single doppler at 18 weeks and further scans only when clinically indicated, and another that received 5 Doppler readings during pregnancy. When compared with the regular group, and after adjusting for other confounding variables, babies in the intensive group tended to be shorter when measured at birth and at 2-3  days of age. There were also reductions in the circumferences of the chest, abdomen and mid-arm, and in the skin-fold thicknesses of the triceps, parascapular and subscapular regions – although these differences weren’t statistically significant.

A later study in Lancet found a similar effect on fetal growth in women receiving repeated ultrasound exams, although measures of growth and development later in childhood (up to age eight) were similar in both groups.

A case control study of 72 children who had undergone a formal language evaluation found that children with delayed speech had a higher rate of ultrasound exposure in utero than normal controls. Their findings suggested that a child with delayed speech was twice as likely to have been exposed to prenatal ultrasound. (Note that this is a correlation and doesn’t prove causation.)

…while other studies suggest ultrasound is safe

On the other hand, a recent World Health Organization (WHO) review of the literature in 2009 concluded that “exposure to diagnostic ultrasonography appears to be safe.”

However, even in this review they did express some concern about the association between left-handedness in males and exposure to Doppler ultrasound. Non-righthandedness is sometimes a marker of damage or disruption to the developing brain. 2

Another review in 2008 concluded:

At this time, there is no specific reason to suspect that there is any significant health risk to the fetus or mother from exposure to diagnostic ultrasound in obstetrics. This assurance of safety supports the prudent use of diagnostic ultrasound in obstetrics by trained professionals for any medically indicated examination.

What are we to make of these conflicting results?

One of the reasons it’s difficult to make any clear determinations from the research is that the methodology of many of the trials is faulty. For example, in a randomized controlled trial in Sweden in the late 70s that found no differences in hearing, vision, growth or learning at age 9 in kids exposed and unexposed to ultrasound, 35% of the supposedly unexposed group actually had a scan. This means there was no true control group.

In fact, there are very few studies at all comparing outcomes between women who have received no ultrasounds at all and women who have received ultrasound during pregnancy. This is the kind of research we need to make an accurate determination of the effects of ultrasound on mothers and developing babies.

Another problem which I mentioned earlier in the article that casts doubt on current safety assessments is that scanning intensities used today are up to 6-8 times higher than they were in the 1990s, when all of the large population-based studies assessing ultrasound safety were done. This means we have no data on the large population level indicating whether ultrasound scanning at the frequency and intensity commonly practiced today is safe.

In a 2002 review of the safety of ultrasound in the prestigious journal Epidemiology, the authors concluded:

Until long-term effects can be evaluated across generations, caution should be exercised when using this modality during pregnancy.

Weighing the risks and benefits of routine ultrasound

The evidence I’ve reviewed here does not prove that a single ultrasound scan at relatively low intensity performed by a skilled operator will cause harm to a developing baby.

However, there is sufficient evidence that multiple pulsed ultrasound scans, or as few as two continuous wave Doppler scans, or any ultrasound scan performed by an unskilled operator may cause harm. There is also a pressing need for large epidemiological studies to be performed using the higher ultrasound intensities commonly used today.

When making a decision to perform any medical diagnostic test or procedure, benefits must always be weighed against risks. It’s rarely a black or white issue. Clearly, if ultrasound was 100% safe with no potential for harm, there would be little medical reason not to perform routine ultrasound during pregnancy.

But the evidence indicates that ultrasound is not risk-free, so we are forced to weigh whatever benefits routine ultrasound might provide against the potential harm it could cause. That harm could be physiological – including the effects we’ve covered in this article – and it could also be psychological. And of course psychological effects like stress and anxiety very quickly produce real physiological changes in both the mother and the baby.

The authors of the 2010 Cochrane review on ultrasound remind us that:

Subjecting a large group of low-risk patients to a screening test with a relatively high false positive rate is likely to cause anxiety and lead to inappropriate intervention and subsequent risk of iatrogenic morbidity and mortality.

Translation: giving all women ultrasounds may end up introducing unnecessary stress and anxiety, which in turn can produce real complications that would not have otherwise occurred. The screening for potential abnormalities can become a self-fulfilling prophecy.

Routine ultrasound also increases the likelihood that more tests will be performed, which could also increase the risk of complications. In a trial of Doppler in 4,187 low-risk pregnancies in France, the only significant result of using doppler was an increase in the number of ultrasound and doppler examinations subsequently conducted. There were no other effects on the management of pregnancy.

And then there is the new trend of non-medical fetal ultrasound (also known as ‘keepsake’ ultrasound), which is defined as using ultrasound to view, take a picture, or determine the sex of a fetus without a medical indication. This practice involves long exposures using 3-D and 4-D ultrasound techniques, which have not been studied adequately, and do not provide the patient with medically appropriate data.

For this reason, major organizations like the American College of Obstetricians and Gynecologists, AIUM and the FDA do not support keepsake ultrasound.

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Recommendations and personal experience

Based on the evidence we’ve reviewed in this article, I recommend minimizing exposure to ultrasound during pregnancy in the following three ways:

  1. Using ultrasound only when medically indicated, i.e. only when a problem is suspected, rather than as a routine screening to determine the sex of the baby or check on its development.
  2. Minimize total exposure time (by choosing a skilled and knowledgeable operator).
  3. Minimize exposure intensity (i.e. avoiding Doppler during the first trimester especially).

Steps 2 and 3 are especially important in light of the lax regulation of ultrasound and the incredibly high variability of skill of ultrasound operators. In the USA, UK & Australia, ultrasonography training is voluntary – even for obstetricians – and the skill and experience of operators varies tremendously. Most operators don’t follow the scientific literature and aren’t aware of the safety issues involved with repeated and high intensity exposure.

In cases where abnormalities are suspected, a woman may wish to have an ultrasound to determine whether an early termination is warranted. The moral, ethical, economic and social issues involved in that decision are far beyond the scope of this article, and cannot be answered through research alone.

I support the right of a woman and her partner to choose what is best for them in this regard; after all, it is they who have to live with the results of their decision.

My wife Elanne and I chose not to have any ultrasound scanning done during her pregnancy, even though she was 39 when she conceived and thus at higher risk for certain genetic abnormalities.

We discussed it at length. In the end, we decided that what we might lose in getting the scans was greater than what we might gain. We felt the stress that a minor or uncertain problem on the scan could produce, and the worry and concern we’d feel waiting for the next scan, and the next one… would interfere with our relationship with our growing baby.

We also decided that we would carry the pregnancy through to full term, regardless of whether an early scan (had we had one) turned up a risk for an abnormality. It took us 2 years of off-and-on attempts to get pregnant, and because of the relatively high risk of false positives and the uncertain results of those genetic tests, we were willing to live without the information a scan might have given us. If it hadn’t taken us so long to get pregnant, or if Elanne had been younger when she did get pregnant, perhaps we would have made a different decision. Perhaps not.

I’m in no way suggesting this is the right choice for everyone. I strongly recommend that you educate yourselves about the risks and benefits of ultrasound first, and then consider your own personality, circumstances and values before making a decision. No one – not me, your doctor, or any other authority – can make this choice for you.

Articles in this series:

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  1. Buckley S. Gentle Birth, Gentle Mothering. Celestial Arts, 2009. pp. 88
  2. Odent M. Where does handedness come from? Handedness from a primal health research perspective. Primal Health Research 1998;6(1):1-6.)
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Join the conversation

  1. P.S. The rate of stillbirths according to one study done for Type 1 diabetics is 19.6%, which is 4-5 times higher than the percentage for non-diabetics. This study also indluded diabetics that were smokers as well as diabetics who did not manage their diabetes or control their blood glucose levels.

    I sincerely wish that information could be gathered only from those that did not smoke and also only from those that controlled their diabetes very well. (Those that has a hba1c percentage below say, 7 or 6 %.)

  2. I am a Type 1 diabetic and am 15 weeks pregnant with my first child. I have had all of the testing possible done including the first trimester nuchal translucency test. All of the results came back very excellent. My blood pressure is excellent. So far this pregnancy has been very easy. I am using a continuous glucose monitor and an insulin pump and am keeping a close eye on my blood glucose levels to keep it below a hba1c of 6%, looking to get it even lower as much as I possibly can, my goal is 5% (non-diabetic ranges are 4.3-5.8%). I am also exercising to maximize the size and health of the placenta. I desperately want to have a natural birth without an induction or c-section and am doing all I can physically do to make this possible. The OB/GYN is trying to force me into an induction and wants to increase the ultrasounds to every week beginning at week 20 and twice a week beginning at week 32. She is already doing them once every 2 weeks. I have done a lot of research and discovered that 5 mg of folic acid is recommended for pregnant diabetics since it has been found to reduce the risks and incidence of stillbirths. I asked my OB/GYN about it and she said she has never heard of this recommendation before. Mind you, I read about this in multiple places as well and went as far as to discover why this was recommended. It has astounded me that she did not know this and additionally did not look into this at all after I had shared this with her. I will be counting the numbers of the baby’s kicks per day as well. I am having an anatomy scan done at 18 weeks and a echocardiogram of the baby’s heart shortly thereafter. I admit I am uncomfortable about the idea of having so many ultrasounds done. I am wondering if I could just do the anatomy, echo and then allow them to do the ultrasounds 3-4 weeks before the delivery but none beyond that in between those tests and now? Even the ultrasounds can still miss a possible placental degradation. Is it possibly fine to avoid the anatomy as well? The frequency of all those ultrasounds just honestly feels like overkill to me and I do wonder if they are truly 100% safe or fine. If it truly is beneficial to do them however, and if I knew there was more of a reason beyond just monitoring and checking, I would be fine with it beyond the last 3-4 weeks worth of ultrasounds. It really bothers me that the doctor is trying to force me into an induction that may very well turn into a c-section if the induction fails. So far, everything is absolutely excellent and I have zero complications. To everyone here, could you share your thoughts concerning this if you have any?

  3. Having had a LEEP you are at higher risk for preterm delivery. The most accurate way of determining if the process of cervical shortening has begun ( prelude to labour) is ultrasound. When studies were done comparing a digital exam ( using fingers) to ultrasound in determining cervical length, the superiority of ultrasound was evident. If you truly feel more comfortable not having ultrasounds then the only option might be a vaginal exam, by the same OB every 2 weeks until 32wks of pregnancy. You will need to accept though that a shortened cervix may be missed until it is clinically evident i.e. too late, and that the risk of this would be losing an opportunity to potentially give steroids for foetal lung maturity in a time frame that might make all the difference between a good and bad outcome.

    (It is not inevitable that you will go into preterm labour; the risk is higher than normal though).

    I do not know any OB’s who would be happy to do this, but again I also know none of the good ones will ever compel a patient to do something she does not want.

  4. Hi Chris,

    Great articles, thank you for writing these.

    I had a leep procedure done a few months before I conceived and my OB says I will need to have an ultrasound every 2 weeks starting at 20 weeks. I truly do not want these ultrasounds but it doesn’t seem like I have a choice. Are there other ways of determining shortening in the cervix? If anyone else has had this experience, I would love to hear your thoughts.

    Thank you!


  5. 1. Not just because a study is published does it mean that it’s results are reliable. It is estimated that 90% + of published studies are of low quality and do not contribute anything to patient care/ knowledge

    2. Dating is necessary- it avoids deaths due to prematurity in circumstances where birth has to be induced for medical reasons, decreases the number of unnecessary inductions of labour ( and attendant complications of the intervention) and allows us to adequately counsel women whose babies may be too premature to survive in circumstances where for example premature rupture of membranes occurs. The entire speciality of OBGYN worldwide agrees with this, as do women unfortunate enough to have required intervention that depended on an accurate gestational age. If you disagree then I guess we all stand corrected.

    3. Medical schools and hospitals where doctors train are not sponsored by equipment companys, neither are we trained by them.

    Perhaps a little more research into the facts might be in order as if you are prepared to make sweeping generalizations based on ignorance of the reality re: training then I personally would doubt the veracity of the rest of what you have said. Then again what would I know as a trained OBGYN? After all I’m part of the conspiracy.

    4. There is no such thing as a free lunch. HRT, x rays etx are safe provided they are used correctly and in the right patients, but like anything in life there will always be someone who is harmed. Drink 4 liters of water a day and you will feel wonderful. Drink the same volume every hour and by hour 5 you will be dead of cerebral oedema . It wasn’t the water that was dangerous, it was how you used it that was.

    5. No one asked you to ‘blindly trust’ anyone but it appears you are doing so by believing everything my eminent colleague is saying.

    • Tarek, it is very hard to change medical practices once they become the “standard of care” no matter how much scientific evidence comes out showing a practice is harmful. Routine episiotomy is an excellent example of this. As a medical practitioner yourself, you must be feeling a certain amount of cognitive dissonance about the question of ultrasounds. The truth is it is very possible that we are grossly overusing ultrasound in obstetrics. Doing a scan at every visit has become the standard of care for many doctors who dismiss the idea that it is even possible that overexposure to ultrasound could be anything but benign. Pregnant mamas have come to expect scans, and it seems that women are getting upwards of six scans per pregnancy. No doubt you are aware of the work of Pasko Ravic, Ph.D./M.D. who has been conducting a 7-year-long ultrasound study on primates at Yale University. The best thing to do would be to contact him directly to discuss the results of his meticulous research, since they have not been published yet. There is mounting evidence that overexposure to ultrasound is causing brain abnormalities in some human fetuses. That must be difficult to think about, given your profession. But instead of remaining anonymous and getting into an internet debate, however useful it may be, it might be better to spend some more time with the scientists investigating this issue and looking at their theories, experiments, and results. I would be glad to have an off-line conversation about this by phone, Skype, or email. If you are interested in deepening your knowledge and understanding about this issue, please contact me.

      • Believe me I’m the last person who cares about ‘standard of care’ as I’m constantly questioning it.

        I think though we need to be a little more nuanced than to claim all ultrasound is harmful and hence should be discouraged or avoided, which it seems to me is the exceptionally unreasonable position being postulated. Evidence changes all the time in medicine and what was practised today is often abandoned tomorrow, revisited in 10 years and reintroduced sometimes with the previous research being rubbished as inadequate ( episiotomy being a great example as most of the large studies did not distinguish between midline and media lateral episiotomy and their different impact on anal sphincter injury and subsequent incontinence as it was much easier to not distinguish between them ).

        The evidence that continuous exposure to ultrasound is potentially harmful, secondary to the risks of tissue heating and cavitation is widely know , hence we are exhorted to limit the time taken to perform ultrasound and to avoid higher frequencies eg Doppler during organogenesis. No one except someone exceptionally ignorant of ultrasound physics would deny this. Furthermore long ultrasound studies with the probe placed directly over a particular tissue for a considerable length of time is associated with mechanical effects hence we tend to avoid doing this except when performing targeted anomaly scans, of which 2 at maximum need to be performed in pregnancy and only in those complicated by anomalies

        . Foetal brain injury, were it happening on a scale suggested would have manifested itself clinically in the form of specific organic brain disease. Where is the evidence this is happening? Cerebral palsy rates have been static since the 1960’s and there are multiple causes, theories and explanations for mental retardation, autism, epilepsy and other disorders that including heavy metal poisoning, teratogenic drugs, older maternal age, chromosomal anomalies, alcohol, drug ingestion, viral infection etc. Why is ultrasound now being victimised as though it were the last piece of the puzzle? Are the effects of co founders like the toxic chemicals found all over our planet e.g. Flame retardant materials in furniture being controlled for? Primate studies are all well and good, but with millions of women yearly in the US alone receiving ultrasounds and delivering healthy babies, with a widened social media presence and a media constantly searching for salacious scandal where are the cases that would prove beyond doubt that it is harmful? Are they perhaps being concealed by some conspiratorial group? Ultrasound has been used for over 60 yrs in medicine, in all age groups, at all stages of life and has an excellent safety record. I am actually very open to new ideas and never actually believe that anything in life is ‘settled once and for all’ but this whole idea seems to me terribly self-indulgent. We live in a society where patients will happily sue their OB anytime something is ‘missed’ , yet want 100% detection of all anomalies, a perfect, stress free ‘natural ‘ birth and everything to run smoothly . Anything that goes wrong must be someone’s fault, seems to be the logic. This is a Paradigm that cannot be perpetuated, especially when the tools we use to try to meet these unrealistic expectations are now being blamed for causing so e of the trouble. Why is the evidence of safety of ultrasound being ignored?

        The reality is there is no intervention of any kind whether drug, imaging or surgery that does not have the potential for harm implicit in it. This does not mean we should abandon those interventions, merely that we must study them thoroughly, use them wisely and stay away from idealistic nonsense of claiming something is ‘completely harmful’ or ‘completely harmless’.

        I look forward to the data you refer to being published in a peer-reviewed journal. Should it meet the standard required of papers purporting to establish causality and not association I will be more than happy to reconsider my position.

        On another note, using my first name in a public forum can hardly be construed as anonymity.

        All the best.

  6. To clarify certain misconceptions: 1. ” Dating” is the most important reason for performing an ultrasound in pregnancy. The biggest killer of babies is preterm delivery, something that cannot accurately be diagnosed if the exact gestational age of a pregnancy is known. It is not enough to have a regular period; studies have shown that ultrasound is more accurate for dating than is last menstrual period. 2. The second biggest killer of babies is congenital anomalies. These cannot be diagnosed without ultrasound and sometimes require several for confirmation. It just happens that at the same initial anomaly scan, sex is determined. This is important to many parents and hence to my mind is a ” medical” reason. 3. A paper presented by a colleague in Europe found that over 75% of ” low-risk” pregnancies subsequently became ” high-risk” so to suggest that some women deserve less care than others is naive at best. 4. IF your OB had this attitude then it is unacceptable, however there is always 2 sides to the story and I won’t pass judgement without both. 5. If memory serves me correct Dr. Northrup is not a radiologist, ultrasonographer or an Obstetrician . She is a Family Doctor, practically none of whom receive any ultrasound training during their residencies. I would suggest that unless you intend to take your car for repairs to your hairdresser, or your boiler to a carpenter that you look very carefully at who is delivering the ” evidence”.

    Millions of us all over the world regularly perform or order ultrasound for our patients. We are yet to see a single complication of ultrasound as used responsibly, like any thing else in life, it is safe. Pregnancy by itself is a risky physiological state, and whilst I agree that we should minimise risk, lets focus on reducing tangible risks before we obsess about theoretical risks.

    Just because a paper is published does not mean we should take its words as gospel, and unless an expert in ultrasound with research experience and proven credibility presents tangible evidence of harm, I would personally advise any pregnant woman to have an ultrasound as suggested by their OB.

    Contrary to popular belief, us OB actually care about our patients, and given that we spend 4 year at college, 4 years at med school, and at least 4-7 yrs training exclusively in our speciality I like to think we actually know what we are talking about. ” Primum non nocere” is the first principle of medicine, and that is something practically all of us live by.

    I would also suggest that anyone attempting to read the literature be trained in critical appraisal, epidemiology or have access to someone who is. If many doctors are unable to correctly interpret the literature after many years of training, with the greatest of respect then someone without the training attempting to understand the individual studies is like a person reading a foreign language with no idea what the words mean.

    Ultrasound is safe and has been established for over 60 years.

    • Dr. Northrup is an OB -> http://www.drnorthrup.com/about/credentials.php

      They are safe? I guess you didn’t read any of the studies linked above? That’s some contrary evidence right there. They used to say hormone replacement therapy, x-raying pregnant women, and even not washing hands between patients were safe but they weren’t! When it comes to my family’s health – blindly trusting people that have been trained by the very companies that produce these equipment and drugs and asking questions later is not good enough for me. If it’s not medically necessary (and no, “dating” is NOT) then I decline thank you very much.

  7. Thank you for a very thorough post on this subject and the links to studies. Dr. Northrup was the first person I heard say she refused ultrasounds in her pregnancies and since then I’ve been doing more research on it.

    First of all, no one is saying that ultrasounds shouldn’t be used when medically necessary or for high risk situations. I think the author is pretty clear that when the benefits outweigh the risks that it’s the smart choice. It’s when there isn’t a medical reason for an ultrasound – like dating, seeing the gender, or just “checking” – it is concerning in light of this evidence.

    I’m 12 weeks pregnant and when I had my first appointment with an OB (that I will not be returning to) she completely chewed me out for declining the ultrasound claiming that it was necessary they get the correct date and to check that I had a “viable” (in other words, alive) baby. She claimed the data was pretty clear that they are safe (but it’s not). All of her reasons for justifying ultrasound was about their convenience and saving them time and money – not about my and my baby’s health. Since then I found out that no one on staff there, not even the midwives, know how to use a fetoscope!

    This is very concerning when we are losing the power to make our own medical choices in the best interest of our and our babies’ health for their profit. Parents do not give informed consent to any procedures when they are not presented with the pros and cons (like listed above) and this needs to end.

    We are currently looking into natural birthing centers to deliver our baby. Hospitals are great and very important for emergency care – but otherwise I don’t feel very safe and cared for when their dollar and time saving is the bottom line.

    • Dina, like you I was very excited to be looking at birth-centers in our city, until I found out that they would be using the mobile fetal monitor every other contraction in the second stage of labor. Now I’m concerned that they are also using the hand held devices mentioned in the above article at every pre-natal visit. Talk about irony?

  8. Have there been any studies regarding effects on ultrasound technicians who do them all day? Does it have any effect on their fetus if they are pregnant?

  9. 1. Can an Ultrasound detect brain injury, dementia, blood clots, and the possibility of developing a stroke, as well as scoliosis, weak kidneys and bladder?

    2. Is an Ultrasound safer than an MRI Scan and CT Scan?

    3. If they use a gel to perform the ultrasound test, then how can they apply gel to the head to do this?

    4. This patient was involved in a motor vehicle accident and since developed a fear of these diagnostic machines such as CT Scans and MRI Scan. She fears that due to the high amount of radiation they are said to transmit in order to obtain the pictures, even though they are said to both work differently, that it may further aggravate her condition . She also has developed claustrophobia and cannot go inside these long, tight and narrow machines and expected to be kept there for an hour until they take their pictures, and does not want to be given any sedatives because she suffers from severe allergies to foods, chemicals and prescription drugs. She also is against having Glandolium Contrast which is said to cause permanent hardening of the muscles and kidney damage.

    I hope someone can give me a reply urgently because we need to know how we can treat her injuries.


  10. Why is less right-handedness a cause for concern? Are there health concerns associated with being left handed?

    • The fact that left-handedness was higher for boys exposed to ultrasound in utero probably means that the ultrasound had an effect on the development of their nervous system. That’s a major red flag.

  11. As someone who experienced many years if infertility and then losses and 3 very high risk pregnancies, I appreciate every single ultrasound that I had most especially the one that saved my son from being stillborn.

    It’s also amazing to me that after taking 2 years to become pregnant at the age of 39 that you would not allow your wife to have an ultrasound. First, there are many abnormalities that can occur in a baby, more so at increased maternal age. Knowing about those issues before your baby is born and being in a facility where that little one can receive immediate care is of utmost importance. One in 100 babies have a congenital heart defect, a lot of which can be detected at a thorough 18-20 week ultrasound. Then that baby can be safely delivered in a hospital with a NICU where it has a much better chance of survival.

    Second, there are numerous issues which can occur with the placenta which would greatly endanger the life of the mother and potentially the baby. Placenta previs, placenta asccretia, IUGR of the baby are just a few. Knowing about those only empowers the mother to seek out the best care available for herself and her child

  12. In the mid 1970’s Sweden had investigated and found with their data that dyslexia was a prevalent outcome. Ultra sound scanning was stopped and only done where there was at risk to mother or foetus. There was a marked drop in dyslexia in Swedish children with the cessation of scanning. The scientific studies were available for all to read at that time.

    Why did the UK continue with scanning? Now dyslexia is rife!

    Dyslexics are extremely intelligent children who see the world in a different format to what we consider the norm to be. They find learning the conventional way difficult and not conducive to their way of thinking and learning.

  13. As an OBGYN I am definitely and aggressively in favour of patients being fully informed about everything done for them no matter how ” routine”.

    Most complications that occur in pregnancy occur in healthy women, more often than not who have no risk factors. That is the sad reality that many of us face.

    Ultrasound is one of the tools that we use to ascertain the health status of a baby. It should definitely be used for indicated purposes but to quote studies without putting the numbers in context, without further describing the background, the populations etc is to misrepresent them and their conclusions.

    Unexpected congenital anomalies, a dead baby, a baby undergrown ( IUGR), twins, a placenta whose location is abnormal or which is invading the uterine wall are examples of complications that occur in all women and that can only ever be diagnosed on ultrasound. By unreasonably spreading the idea that ultrasound is a potential danger when the large studies done over time suggest otherwise ( I note Dr. Kresser’s point about most having been done with the older machines) we are only decreasing the ability of anOBGYN to reassure a woman that her baby is well and to detect issues that can unexpectedly occur.

    Compare the theoretical risks of ultrasound to real risks of pregnancy e.g. 20% risk of miscarriage, 1-5% risk of preeclampsia ( complications can include the mother dying in extreme circumstances), 1-5% risk of diabetes in pregancy ( risks to both mother and baby ) among others. How can it now be said to be deleterious? Compare the potential risk of caffeine ( increased miscarriage rate noted in some studies), smoking ( increased miscarriage, low birth weight babies), being overweight ( increased risks of all complications) with ultrasound and ask yourself why is a theoretical risk being placed more at a premium than documented risks?

    Millions of women all over the world have ultrasounds daily. Where are the reports of anomalies that were caused by them? Or of babies that experienced a complication directly attributable to ultrasound? We live in a world where disasters like Thalidomide cannot be hidden anymore, where lawyers are trigger-happy and where patients thankfully no longer blindly follow their doctor’s advice. Events can no longer be concealed so where are they?

    If you want to know both sides of the story you must ask someone directly involved in the field and challenge their advice / “facts” with that of others, either also working in the field or whose education/ reading qualifies any opinion they may have. If a doctor specialising in disorders of the liver was to write a book on heart surgery, noone would take it seriously as that individual, no matter how informed theoretically, would lack the knowledge practically to inform their opinions. Family doctors do not do ultrasound hence I would view the “evidence” presented in the book referenced in the article with extreme scepticism.

    There is no such thing as a risk-free pregnancy. Birth is a natural process, but that does not stop hundreds of thousands of young and healthy women yearly dying in childbirth. We can only manage risk to a certain extent, but should not create a false dichotomy where one either chooses ” medicalised” or ” natural” pregnancy and childbirth. To imply that one or the other is ideal is patently ridiculous as one implies that all the advances of medicine have been futile and the other that medicine has all the answers, two positions which are extreme in nature and against the balance most of us seek in all aspects of our lives.

    • Due to the fact that ultrasounds could be causing a host of issue that can’t be directly linked back to the ultrasounds is enough of a reason for me to not want my babies being exposed to the heat, and high frequency waves. You are saying bc babies are being born healthy, then that is assuming the ultrasound hasn’t done damage to any of the internal workings. Would a slightly weakened immune system be apparent at birth? Or some mild-severe neurological problems? There are so many crazy new disorders and diseases with babies these days. There’s no evidence against ultrasounds bc there’s no testing. But personally, 100% of the babies of friends I’ve had who had multiple ultrasounds have had issues with sleeping as babies, and having worse than normal immune systems, babies that get sick ALL the time. And as toddlers they seem slightly autistic or “off” socially.. not enough for them to be considered autistic, but enough to see when all the kids get together, which ones are “different” my daughter who I only had one ultrasound with randomly got a perfect circle of eczema on the side of her knee after I stopped breastfeeding then it showed up in other areas on her legs. What I hear is that, oh that’s normal. The problem is that yes it really could be anything. It could be the result of the ultrasound damaging cells that were forming in her immune system and around her skin in those areas. But eczema is surely on the rise, and nobody can pinpoint it. I am anti ultrasound bc I would rather take the risks of the unknown anomalies. I believe I should be informed about proper nutrition to keep myself and babies healthy and then deal with any emergencies if they arise. If other people want the option of having a slew of ultrasounds, they should. But my decision to not want ultrasounds should not be treated as if I’m somehow endangering my “twin” babies. The evidence is not pointing to the safely of ultrasounds, but the fact that NOBODY knows. That unknown means something to me.

  14. contained in his article regarding Doppler being more dangerous as continuous vs. pulsed and whether more dangerous 1st trimester vs. 2nd trimester (when baby’s bone more developed).

  15. I find it quite disturbing that Chris failed to reply to two very good questions posed by other readers (Lotklear from Oct 2013 & Elizabeth from July 2011) regarding conflicting information c

  16. Great article. Have a great list of references as well. I cannot agree more with this article and some of the comments other mothers have mentioned.

    It is always a struggle to balance between “check to see if the baby is ok” and the potential damage these types of diagnostic tests may cause. The issue is that many people, and even doctors believe ultrasound devices are safe without really looking into this.

    A friend of mine had some bad experience as some of the mothers were mentioning about, and her story motivated me and two other engineering friends to start a project – providing a passive tool that allows expecting mothers to hear the baby’s heartbeat passively and therefore safe.

    I truly believe that many parents will gain benefits from this device. How does it work? Sound waves from your baby’s heartbeat are focused onto an ultra-high sensitivity microphone through a fetal stethoscope, and it then Interfaces with your smart phone device. This has allowed us to perform audio filtering in order to reduce ambient noise, thereby improving the sound quality of your baby’s heartbeat. It is a passive detection method, and the sound quality is significantly better than a normal fetal stethoscope, so you will still be able to hear the baby’s heartbeat as long as the position of the baby’s heart is facing outward.

    Find more here: http://www.thelittlebeats.com.

  17. Personal experience: (I had multiple ultra sounds with my youngest, because of high risk issues, but unrelated issue surfaced for this daughter later, I think due to ultra sounds)My daughter is now 25 (born 1988), and has had some of the issues surface discussed in the article! Plus when she turned 8 we discovered she had an arachnoid cyst. Although her growth issues surfaced in growing pains nearing the preteen years. She is 5 foot 10 now. But during growing years, I saw her litterally grow overnight at times, and experience great intense pain.
    The neurolgist thought the arachnoid cyst happened in-uteral (during pregnancy), but funny thing, we had multiple ultra scans checking to see if she my have any cranial hemmoraging like my other 2 babies. So I know she did not, reflectively what I have learned about troubles with arachnoid cysts, I suspect it may have manifested around 6 months old as I recall behavior incidences that happened at key times.. The Cavitaion concerns… well the nuerolgist had discovered her hearing had not fully developed (age 9), this is where the arachnoid cyct(s) are. So she had slow speach development, and had dexlexia. She does have some hearing, but where there are multiple sounds/noises it is difficult for her to single out and dicipher what someone is speaking to her. I.e. she or another person talking over a phone or cell phone is really frustrating for her if there are back ground noises on her side or whom she is speaking with. Or in an area where machinary is running, she has more trouble then others would, and can become very agrivated by such situations! Her stress levels elevate and become more problematic more then others under stress, even being overly exhausted can become a stress and it is important for her to get needed rest before making important decisions or addressing emotional topics.
    She is an awesome talented lady, with a beautiful spirit, but the handicaps as a result of this issue surely become problematic! We do know the better the diet, the better is life in every capacity, whole foods important! Lots of fresh raw fruits and veggies even better!!! I hope this experience of life learned from those affected by the affects will benefit another. If I had things to do over again, I would have only allowed 2 of those ultra sounds and even considered, especially if I had known then what I do about diet now, no ultra sounds, etc, I would have just eaten 80 percent raw fruits and vegetables, no meat and no dairy.

  18. Your sources indicate PULSED waves are more of a thermal risk and should be avoided. Your article states “Doppler ultrasound, which uses continuous rather than pulsed waves, has been shown to cause significant heating”. So which is more dangerous- Pulsed waves or Continuous waves. Further, my reading indicates Doppler can either be pulsed or continuous. Please clarify.

  19. Hi Chris,

    My husband and I are weighing whether to have an ultrasound scan. If I were to have one, I’d only have one.

    I’m at 17 weeks and have read on several web sites that the scan tends to be more/less dangerous depending on what stage of development the baby is at. What would be a safer window in which to have the scan based I guess primarily on brain development?

    I wish I had researched info before asking to have a doppler scan at week 14 🙁 My mom had told me to research the health risks of ultrasounds, but I was unaware that a doppler and ultrasound are similar devices, and I was in a country where internet was not readily accessible to me.

    I am 26 years old and I shock most of my peers when I say I’m not sure whether we’re going to have an ultrasound or not. I can’t believe how clueless/careless my generation is *sigh*


    • Thank you Jennifer. Of course now I am worried that any damage may be done since I’ve already had 5 ultrasounds. Is there anything I can do to reverse any negative effects going forward?

      • That’s an excellent question Sarah. The difficulty here is that every human responds differently to potential toxins. My grandfather smoked like a chimney but lived to 89 and never had a cough a day in his life, whereas Christopher Reeves’s wife died of lung cancer and never smoked. I think the best thing to do is what I am sure you are already doing: have the healthiest pregnancy you can by eating whole foods, exercising every day, reducing your stress levels (that one is so important and so often overlooked), and avoiding other sources of toxins (including edible food-like substances that aren’t really food and skin products that have harmful chemicals in them.) If you can check my book out from your local library, there is a lot in it about how to have a healthy pregnancy and childbirth. It’s called THE BUSINESS OF BABY: What Doctors Don’t Tell You, What Corporations Try to Sell You, and How to Put Your Pregnancy, Childbirth, and Baby BEFORE Their Bottom Line. There’s an entire chapter on ultrasounds.

      • To support Jennifer’s advice with regard to maximizing fetal recovery. Environmental hazards can inhibit recovery from ultrasound trauma, such as the unventilated gas stove, which is like a car idling in your kitchen. This is another political topic. Flu, colds, and virtually any disease can indicate stove or boiler exhaust poisoning. Venting is tricky as it always requires two vents, inlet and outlet.