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

Heat

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

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.

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:

  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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Comments Join the Conversation

  1. Leigh Porter says

    Mike – Fetal heart rates taken during an ultrasound are pulsed and the monitors used in the doctors office and during labor are contiuous wave – Both are two different kinds of ultrasound doppler. I am a ultrasound sonographer registered with the ARDMS

    http://en.wikipedia.org/wiki/Medical_ultrasonography

    http://www.articlesbase.com/babies-articles/baby-fetal-heart-rate-monitor-and-reader-doppler-1446747.html

    http://www.echoincontext.com/doppler01/doppler01_09.asp

    http://www.karlloren.com/ultrasound/p74.htm

  2. Terry says

    Did you have any trouble getting the health care provider to go along with your wishes.I was wondering how great the pressure to have a routine ultra sound is.

    • Chris Kresser says

      We haven’t interacted with the medical establishment during our pregnancy. We’re having a home birth with a midwife, and she supported our decision not to have an ultrasound.

    • Adele says

      I had heard of several friends w/ problems w/ this. Plus, I was “old”. But I had no problem. I explained to my doctor that we would not abort our baby if anything was wrong and considering the stress of “false positives” I saw no need to proceed. I picked a prolife doctor who would not pressure me about fetal testing/termination.
      The hard part is avoiding the heart checks w/ the hand held doppler. I brought my own fetoscope and the doctor gladly used it. Keep in mind, many doctors/mw may not know how to use a fetoscope, so you’ll have to bring along some instructions!

  3. says

    Yes, the electronic fetal monitor is probably the worst form of ultrasound because (in most hospitals) women have it ALL THE TIME (hours and hours and hours), and (unlike the ultrasound scan), it is a continuous form of ultrasound! Eek! And, beyond that, no studies have been done that have proven the benefits of the electronic fetal monitor (because there are none) over intermittent fetal monitoring (with a, ahem, Doppler, or fetascope, which you’re going to find in a hospital setting). The only thing the electronic fetal monitor has proven to do is to increase the incidence of c-sections when it is used.

    That being said, although most hospitals have women wear the EFM throughout labor, if a woman has the knowledge to, she can ask that it be removed (although, most hospitals will still require an initial 15 minute strip upon checking in).

    • Adele says

      The problem is a mom must have continuous monitoring if she takes any drugs at all. Epidurals/pitocin can be very dangerous to babies so it is important to get the readouts. In my area, we have a 40% induction/augmentation rate and a 95% epidural rate. But otherwise, I agree…totally unnecessary. I had no interventions so my doctor said I only needed 5 minute strip per hour. Which was done very easily and without me hardly noticing it.

      • E B says

        EFM is not a reliable source of information about the baby’s well being. I cannot remember the exact statistics, but it very, very often provides a “false positive” (that something is wrong when it in fact was not) and other times the EFM will indeed miss actual distress. These facts are alarming and surely contribute to today’s obscenely high c-section rates. It is a poor diagnostic tool, even when drugs are used. If it was accurate, yes we should use it in moderation when a women has had interventions. But since it is not, why are doctors and nurses so glued to those read-outs?

  4. says

    Can you clarify one thing for me, in your recommendation, you state, “Minimize exposure intensity (i.e. avoiding Doppler during the first trimester especially).” During the first trimester especially, but from the previous information, it seems as though the doppler would be more risky in the second and third trimester because of the bone formation that is already present in the fetus. ” 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.”

    Also, I want to clarify- this includes the doppler used for hearing fetal heart-tones?

    How do you know if the ultrasound is done using doppler continuous waves vs. the waves that are seconds apart?

    Thanks for putting all of this information into one (two) articles, that I can easily share with others.

  5. says

    Also, I appreciate that you mention the undue stress that could cause it’s own problems. The stress on the mother who may not know if her baby is ok- would potentially be outweighed by the benefit of the ultrasound or doppler verifying that all is well with her growing child. It goes both ways on this topic!

  6. Gordon says

    Chris, I read this post immediately AFTER our 5 child’s ultrasound yesterday afternoon. Nice timing :) All I can say is YIKES. My wife will be turning 35 before delivery so there is pressure for interventions. However, we’ve done well with 3 VBAC’s after our first child’s somewhat urgent c-section (breach). No drugs either. I will share that there is an increasing interventionist mentality creeping into America’s birthing experience – even in the 9yrs since we started prenatal care. Many people thought it was quaint we didn’t find out the sex of our first child. Now, they are verging on angry. The tech told us about 90% find out now and that she certainly saw a recent increase.
    My advice to those facing medical births in hospitals is to find a good midwife and doula – at least for the first couple births. It’s too easy to cede authority to medical professionals when personal emotions are involved, and their objectives are significantly different from the parents’.

  7. says

    Chris, my wife was 39 when she was pregnant with our daughter. At that time (1997) we followed all the doctor’s advice. She had ultrasound, where we found out we were going to have a daughter. She also had amniocentesis. I’d be curious what you think about that. Maybe another blog post :)

    Hope all goes well, with the pregnancy and delivery. Very exciting :)

  8. Sofie says

    I had a miscarriage in January and got pregnant again in May. Because I was/am considered high-risk, I had an ultrasound at 8 weeks (which the insurance company won’t cover anyway cos it’s too early). I have since had two fetal heart rate monitoring two weeks apart. What are your thoughts on that. At this stage, I’m willing to talk my husband out of having any more scans if it’s going to put our baby at any kind of risk no matter the magnitude. Coming from Africa (now in the US), I can testify that people have survived without it an still do have healthy babies. If I don”t need it, i wont have it.

  9. katie says

    Hello Kris. I have a quick question for you. I said no to all ultrasounds and we made that decision even before i got pregnant. I had no idea a doppler uses an ultrasound wave and when i asked my doctor about what that device really is in response she said its just a microphone, 3 month later i find out it does use ultrasound waves. I feel terrible about it and do not trust my doctor and will not go back to her. I am 26 weeks now and the last time she used a doppler on me was last week. I am very concerned about it cause she used it 4 times. Should i be worried?

    • Chris Kresser says

      Katie: I don’t think there’s any cause to worry. Keep in mind that we’re talking about very small increases of risk here, and the vast majority of women who get multiple ultrasounds and dopplers have no issues. I’m just a fan of being as cautious as possible.

  10. MommyTheorist says

    As a mom who hopes to have more children, I really value the information presented in this article. However, as an editor, I see several typos that should be corrected. It’s important to know that an author presenting scientific research has taken the time to carefully proofread hIs work. It’s hard to trust the content when quality has not been attended to. I see this a lot and recommend professional proofreading services when disseminating information that is this valuable and important.

  11. says

    Thank you so much for posting this! I was completely unaware of these risks and because of problems with my last pregnancy my doctors have recommended I get more ultrasounds than normal if I get pregnant again.

    • Medical Sonography Student's Review says

      Honestly, I see a lot of self-contradicting information that is bordering on inaccurate. For starters, as a medical student, I have learned that any animal testing that is conducted needs to be taken into account that their bodies and chemical compositions are somewhat different from the human body. Any testing completed on animals should be taken with caution since humans can have different reactions than what the animals had when testing the effectiveness of medical devices (in this case) or the use of medications for treating disease.

      Secondly, as Mommy Theorist has said, typos are a big no-no when writing scientific articles. As a medical student, we are told that you have to carefully write out your papers and make sure they are proof-read before submitting work. This is to get you used to checking (and double checking your work) so that you do not make any mistakes. Any mistakes made on patient charts can be very bad. Especially if your quality of care should ever be questioned. Any mistakes made on patient charts can be used against you in a court of law should you be faced with a law suit.

      Third, you say in the article that ultrasounds are bad for the developing fetus. Everything someone does can have positive and/or negative effects on a fetus. It’s not different from smoking, taking over-the-counter medications for minor ailments, hot baths, or even simply breathing city air. However, you made a comment in the comments section that ultrasounds have very small risk and that one should not have to worry.

      All in all, what I am trying to say is that if you decide on writing an article on the effects of ultrasound on fetal babies, then one should present both the positive and negative effects of ultrasounds. This article is shown to have multiple biases and that in of itself can be a bad thing as it can show readers that you are only interested on presenting only one side of the story.

      Wishing you the best of luck in your future articles.
      Sincerely yours,
      Concerned Med. Sonography Student

      • Janet says

        I think he did talk about both the positive and negative… his concerns seem genuine, legitimate and unbiased to me, while yours are obviously going to be biased because you’re a med sonography student, and if you open your mind to the possible negative side-effects, your whole career could be out the window. Sounds like you’re defending your career choice to me.

  12. Andrea says

    Hey moderator, feel free to *not* post my previous comment reply to the person who scolded you for typos. It was written in haste and may only further aggravate her. ;) Thanks and thank you also for the great article! I am a doula and I appreciate this info, however minimal the risk may be I also like to err on the side of caution when it comes to unnecessary procedures.

  13. Jen says

    I thinks it’s absolutely prudent to be cautious about anything that may have consequences we can’t know about, however, if you are going to have a website with a slant that is likely to scare many expecting parents, you should at least ensure your “facts” are accurate. Pulsed-wave doppler is in fact more problematic than continuous wave doppler. Hand-held dopplers and the contiunuous monitors used during labour are continuous wave and they work by using very low power levels and I can find no information of safety concerns with that form of doppler. It is actually the pulsed waved doppler, which gives images and colours, that is much higher intensitiy; it’s often used in high risk pregnancies to evaluate arterial and venous blood flow through the placenta, and it is that kind of doppler that has the concerns re: heat, cavatation, and acoustic streaming.

    • Amaar says

      So @ Jen – you feel a little caution cushioned with wrong information about pulse vs doppler- reflects that ultrasound with a trusted medical professional should’nt be a cause for concern?

    • Moddy says

      I don’t think any of us have a problem with ultrasounds being used in high-risk pregnancies – when there’s already an indication of problems is exactly when ultrasound should be used.

      I like to assume that this was an honest misreading, but I’ve seen way too many people with an agenda to push “misunderstand” advice and then claim it’s too dangerous to follow.

  14. Suzanne says

    Interesting articles, thank you! I went to see my midwife today, I had decided not to have any ultrasound scans and told her that. I agreed that she could have a listen to the heartbeat. I stupidly assumed what she was using was a stethoscope – nope! A Doppler handheld, I spotted the name as she used it – I asked her to stop using it, but she’d already used it for a minute or so by then. I was furious! With myself for not being more forceful and asking exactly what it was, with my partner for not asking any questions at all, and with the midwife for using ultrasound equipment on me when I’d specified I didn’t want that. I realise one must be hyper-vigilant and informed at all times, and extremely assertive too, and asking all the right questions. It seems this has happened to other of your readers too. Must one stay ENTIRELY out of the system to avoid this kind of thing happening?!

  15. says

    I appreciate this article and the information you have presented. I’ve found that doctors are astonished, and often angered, if you tell them you do not want an ultrasound.

    There is one aspect of ultrasound danger that you did not dwell on in this article: it seems to cause excess migration of brain cells. An M.D. at the University of Louisville and an M.D. researcher at Yale University are investigating whether ultrasound exposure is the trigger for autism. (Autistic brains, we know from double blind studies, have 10-15 percent more minicolumns.)

    I explore this connection at some length in the book I have coming out in April called THE BUSINESS OF BABY (Scribner April 16, 2013).

  16. S says

    Interesting…. I had a miscarriage right after my first ultrasound, which showed everything was normal (at 5 weeks). Left clinic, came home, started bleeding. Coincidence? Who knows, but next time I won’t let doc scan me until much later.

  17. Donna says

    I just learned that I must have failed my OGTT test as my doctor called to tell me they are recommending me to a gestational diabetes management specialist as I may be have GD. First of all, I have been following a fairly primal/paleo diet for the last two years. In pregnancy, I’ve been drinking a fruit and veggie smoothie (one banana, blueberries, strawberries, spinach, and kale – no added sugar) that I make myself. I don’t think I hit 75g of sugar in a day so of course I will have elevated blood sugar during the OGTT.
    I have been told that as part of the monitoring, they will be doing more ultrasounds and potentially prescribe medicine, neither of which I want.
    Am I really at risk of GD and need this monitoring? I am worried about the adverse affects of increased ultrasounds (I am at 24 weeks) as well as the impact on my wishes for a natural childbirth. Please advise!

    • Bruce, Med Student says

      Dear Donna,

      I would like to provide some of my understanding about Gestational Diabetes and regarding the Oral Glucose Tolerance Test(OGTT) that they have given you.
      First of all, I would like to start from the physiology of pregnancy. Pregnancy itself is undergoing a process where there is sudden change in the level of hormones in your body and the fluctuation in hormones itself will cause a physiological insulin resistance. In a another way, it means the level for your body able to to tolerate glucose will be less than a non-pregnant lady. With this insulin resistance developed(only in pregnancy), pregnant mothers will have higher blood glucose reading. Thats where the OGTT comes in. In OGTT, we perform this test as a guideline to find mothers predisposed to have Gestation Diabetes. Its just a guideline. Nothing is called a perfect test. However, we are trying to reduce the chance of GD because we would like to prevent some possible complications in the future, eg: Big baby, post delivery hypoglycemia in newborn, etc.
      Another thing, fruits contains fructose, which is still a simple sugar which body digest easily. The effects are similar with glucose. Plus, I believe you are not only drinking ONE smoothie for the WHOLE day perhaps? Glucose comes in lots of food. I do like it if you provide your meal list.

      Well, I would like to apologize with my limited knowledge as a medical student. However, please read more references and listen to both side of stories before coming to conclusions. I wish you have a pleasant pregnancy.

  18. Sarah says

    I am considered high need for monitoring due to loss of twins prematurely at 23 weeks last year and now a low lying placenta. I have had 5 ultrasounds already and numerous Doppler checks. I still have more ultrasounds scheduled but now I worry whether there any really any benefits to so many ultrasounds. It won’t change my outcome so should we just wait for one last ultrasound near the end of term? Always something to worry about! Thank you for sharing the information!

    • sara says

      Sarah, I’m not sure whether this might help you feel a bit less concerned, but I had a friend who had a low lying placenta and had ultrasounds every month like you’re having, and her child is perfectly healthy, now an extremely bright 16 year old.

    • Suze says

      Hon, whilst i’m not qualified medically, i wanted to let you know about my neighbour who lost twins at 22 weeks. With her second pregnancy (also twins) she was hospitalised at 17 weeks and given ultrasounds every few days until she hit 27 weeks and the twins were born. They are now healthy, beautiful 4 year olds. I can’t make a comment about how many ultra sounds you should have in the future, but please don’t worry about the ones you have already had. I’m sure there is a healthy balance there somewhere. Please try and relax and all the best with your pregnancy!!

    • Sarah says

      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?

      • says

        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.

      • says

        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.

  19. Mae says

    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*

    Sincerely,
    Mae

  20. Lotklear says

    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.

  21. Gail C. says

    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.

  22. says

    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.

  23. Mommy2B says

    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

  24. Mommy2B says

    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).

  25. Tarek says

    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.

  26. helen mccomish says

    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.

  27. Cassie B says

    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

  28. Marie says

    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.

    Marie

  29. Mary E says

    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?

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