thread: ultrasounds

  1. #1

    Mar 2004


    does anyone know if there are any harmful side effects to ultrasounds?

  2. #2
    BellyBelly Member

    Jun 2005

    Ive been reading a lot about ultasounds and there have been no reported side effects from the use of ultrasounds at all that I have come across. They are perfectly safe for the baby and the mother.

  3. #3

    Mar 2004

    I did a bit of hunting and came across a really interesting article at a source I trust. Since I can't post the link I'll just cut and paste it.

    Physical effects and research
    Many parents ask whether the use of ultrasound is safe during pregnancy. The answer is, at this stage we think so, but we cannot be sure because there is insufficient research to confirm it. The following is an explanation of the known physical effects of ultrasound and how caregivers try to minimise them when using this type of technology on pregnant women and unborn babies.

    HeatingUltrasound heats body tissues and has been shown to create temperature changes of up to 40-45o Celsius at 1MHz, to a depth of 5cm. The higher the ultrasound frequency, the faster the tissue can heat up, with 3MHz heating tissue 3 times faster than a 1MHz, but to less depth. The amount of temperature rise depends on the type of body tissue absorbing the ultrasound waves, with the highest absorption being into bone and the lowest absorption into amniotic fluid, with varying levels of absorption into other body tissues.
    This physical 'heating' effect is the basis of therapies using ultrasound for treating injured muscles and tissues (as well as other medical applications), known as 'therapeutic ultrasound'. However, therapeutic ultrasound generally involves continuous ultrasound waves and long 'dwell times' on one area of the body. Diagnostic ultrasounds (for creating images during pregnancy) are intermittently 'pulsed' with the aim of reducing heating of the body tissues and hopefully making ultrasound safer for the unborn baby. Vaginal ultrasounds tend to use higher frequencies so they do not travel as deep, because the transducer is closer to the baby, but are potentially more likely to heat the baby or surrounding tissues.
    Ultrasound machines used in the 1970's to 1980's had comparatively lower power outputs than machines used today. Many modern machines are now equipped with inbuilt safety features to help prevent power output limits from being exceeded, but there are no 'standard levels' and no regulations. There are concerns in Australia (and in other countries) that standards do not exist, with the level of ultrasound doses varying by up to 5,000 times (according to the machine used), even though the level of the dose used does not generally affect the accuracy of ultrasound results.
    The World Federation for ultrasound in Medicine and Biology (WFUMB) states that ultrasound temperature rises of less than 1.5o C may be used without reservation but that temperature rises of greater than 4o C for over 5 min should be considered potentially hazardous. However, temperature rises are difficult to measure and this guideline leaves a wide range of temperature changes (1.6 to 3.9o C) without specified time limits, at the discretion of the ultrasonographer.
    NOTE:It can be difficult to calculate the actual 'dose' of ultrasound given by any type of machine. Estimates are based on the way the operator uses the devices and 'dose estimates' make assumptions about 'peaks' and 'averages' of energy. Calculating a dose is further complicated by the fact that ultrasound beams scatter and reflect on some tissues and are absorbed at differing rates by other tissues.
    As a general rule, ultrasonographers are advised to keep ultrasound exposure of unborn babies 'As Low As Reasonably Achievable' (referred to as the 'ALARA principle'). This means performing the examination required in the minimum period of time, to reduce unnecessary exposure. Ultrasonographers are also conscious of keeping 'dwell time' over a specific area to a minimum, to reduce any body tissue heating.
    The use of Doppler ultrasound involves higher ultrasound intensities and often continuous frequencies (rather than pulsed). Its physical effects still remain a concern, mainly because of the increased likelihood of tissue heating. The European Committee for Ultrasound Radiation Safety has published statements on the use of pulsed Doppler measurement in unborn babies and states that its routine use during the first 12 weeks of pregnancy is considered inadvisable at present. The effects of elevated temperatures may be minimized by the operator keeping the time during which the beam passes through any one point in tissue as short as possible.
    Cavitation Cavitation is the formation of small bubbles in body fluids, forming as dissolved gases come out of solution from the heating effect of ultrasound waves. The bubbles form, expand and contract then collapse, placing pressure on cell walls. This can potentially cause cell damage and has been shown to cause bleeding in the lining of lungs and intestines of animals. It is not known what effect cavitation may have on a developing baby (if any) but it has been questioned as a possible cause for 'left-handed' tendencies in boys exposed to ultrasound.
    Streaming Streaming is a term used to describe a level of pressure exerted by ultrasound waves moving through body tissues causing body fluids to flow in the direction of the ultrasound waves. This has the potential to work against the natural flow of blood through blood vessels. At this stage, fluid speeds are thought to be low and unlikely to cause damage to an unborn baby.

    The research
    Ultrasound for medical use was first discovered in July 1955, when a Scottish obstetrician (Dr Ian Donald) borrowed an industrial ultrasound machine (used to detect flaws in metal) to examine abdominal tumours in some of his patients. In doing this, he noticed that the tumours produced different shaded images or 'echoes'. He soon started using the device on pregnant women to view their unborn babies. Before long, articles were published in medical journals and within a few years the use of ultrasound became widespread throughout the world. Therefore, ultrasound use during pregnancy was extensively embraced, long before any research was conducted to determine its safety.
    Some caregivers and consumer groups have expressed concerns about the lack of research into ultrasound and a few have compared it with the previous use of X-rays during pregnancy, in that x-rays were believed to be safe for about 50 years, until long term research revealed that it could increase the likelihood of an exposed child developing leukaemia later in life. Once this was discovered, the use of routine X-rays during pregnancy were virtually ceased.
    Research relating to the use of ultrasound (mainly animal studies) did not start being published until the late 1970's and human studies started to become available in the 1980's, with more rigorous randomised controlled trials and longer term studies being published during the 1990's.
    Surprisingly, even after nearly 50 years of use on pregnant women (and with almost universal acceptance), there is still insufficient comprehensive research available that can truly evaluate the effects of ultrasound exposure on pregnancies and unborn babies. This makes it very difficult to draw reliable conclusions about the safety of diagnostic pregnancy ultrasounds or create clear guidelines for its responsible use. At this stage, most reports conclude that there are NO obvious adverse effects, BUT advise caution and the need for further research to confirm this.
    Unfortunately, the current widespread use of ultrasound makes additional research increasingly difficult. This is because a large group of women would be needed who were willing to allow themselves to be randomly allocated to a group selected for 'no ultrasounds' (unless absolutely necessary), so they can be compared with a similar group of women and babies who are exposed to ultrasounds during pregnancy.

    WARNING : Even though ultrasound is thought to be probably safe during pregnancy, the following information aims to outline some of the main studies that have concerned caregivers and consumer groups over the years and where we are at so far. This summary is not meant to scare you, but to make you aware of a few issues surrounding ultrasound use.

    1975 - A study was published comparing babies exposed to Doppler ultrasound and babies who were not (the mother was unaware whether the machine was turned on or not). During the procedure, the babies exposed to ultrasound were more than 90% active than the babies who were not. This prompted questions as to whether babies 'reacted' to ultrasound or could hear it. No studies have been conducted since to evaluate this finding.

    1979 - A study was published exploring the use of ultrasound and its possible side effects on animal cells exposed to ultrasound under laboratory conditions. The DNA and growth patterns of the cells abnormally changed and persisted for many generations (Liebeskind et al. 1979) and another paper demonstrated DNA changes in the surface of human cells (Liebeskind et al. 1979). These studies were unable to be replicated by others but it was theoretically suggested that prolonged and/or repetitive exposure to ultrasound may have side effects for unborn babies (Baker and Dalrymple 1978).

    1984 - American obstetricians published a follow up study of children aged 7 to 12 years who had been exposed to ultrasound before birth at 3 different hospitals in Denver and Florida. The exposed children were more likely to have dyslexia and be admitted to hospital during childhood (Stark et al 1984). This was not a randomised study and there was insufficient information regarding the timing of when the ultrasounds were performed.
    Two studies virtually ruled out any possible links between cancer in children up to 5 years who were exposed to ultrasound (Kinnier Wilson and Waterhouse 1984, Cartwright 1984), but possibly indicated a slightly increased link for leukemia in children over 5 years. This has not been confirmed.

    1987 - A study of 3 to 5 day old newborn rats exposed to ultrasound were shown to have damage to the covering of their nerves (called the 'myelin sheath') promoting concerns about possible damage to an unborn baby's nervous system (Ellisman 1987). This has not been proven.

    1990 - A study looking at physiotherapists working with ultrasound equipment for 5 to 20 hours per week indicated that they may be at increased risk of miscarriage (Taskinen et al. 1990). Another study of 9,000 women from Helsinki showed an increase in miscarriage after the 16 to 20 week ultrasound - 20 babies in the ultrasound group miscarried vs 0 babies in the control group (Saari-Kemppainen et al 1990). A small study from The US suggested an increase in premature birth for women having regular weekly ultrasounds during late pregnancy (Lorenz et al. 1990).

    1992 - A Norwegian study followed up 2000 children aged 8 to 9 years. They were randomly allocated into 2 groups with half their mothers having a routine ultrasound at 16 to 22 weeks and the other half having no ultrasound. There was no noticeable decrease in the children's reading and writing skills, although the authors noted that ultrasound machines used in the early 1980's gave lower intensity of exposure than scanners used currently (Salvensen et al. 1992).

    1993 - An Australian study of 2834 women were randomly allocated into 2 groups. One group had a routine 18 week ultrasound and the other group had 5 additional Doppler ultrasounds at 18, 24, 28, 34 and 38 weeks. The babies exposed to more ultrasounds during pregnancy were 30% more likely to weigh less, an average of about 30 grams (Newnham, 1993). Although this difference was not evident by the time the children reached 1 year of age (Macdonald et al 1996).
    A report on Norwegian children aged 8 to 9 years exposed to 2 ultrasounds after 19 weeks of pregnancy showed that boys were more likely to be left-handed (Salvesen et al 1993).
    A study of 15,000 women in the USA looked at women who only had an ultrasound if their doctor thought they had a problem (45%) and were compared to women who did not have any ultrasounds during pregnancy (55%). There were no differences in the health of babies at birth, supporting the idea that routine ultrasound scanning does not improve the health of babies (Ewigman et al. 1993).
    An analysis of all randomized controlled trials (totaling 16,000 women) showed no improvement in the health of babies by the use of ultrasound during pregnancy. There was a reduction in the amount of babies who died after birth, but this was brought about by an increase in parents choosing to terminate pregnancies of babies thought to have an abnormality.
    A small Canadian study suggested that baby boys exposed to ultrasound were more likely to experience delayed speech when exposed to ultrasound at some stage during pregnancy (Campbell 1993). This has not been confirmed.

    1994 - Newborn mice exposed to ultrasound were shown to experience bleeding in their lungs from the effect of cavitation (Frizzell et al. 1994). This was confirmed by other later studies looking at the effects of ultrasound on baby pigs (Dalecki et al. 1997)
    1998 - A long term study from Sweden comparing men born between 1973 and 1978 (7,000 exposed to ultrasound and 170,000 not exposed). The exposed men were more likely to be left-handed (32% more than expected). In an average population, only about 9% are expected to be left-handed (Kieler et al, 1998). The results suggest that some of the men who were genetically expected to be right-handed had actually grown up to be left-handed. Although being left-handed can be seen as normal, the concern lies with the fact that a person destined to be right-handed can become left handed if there is slight damage to their developing brain. Again, this research is based on the use of early machines, which have much lower power outputs than current machines.

    2002 - Meta-analysis of all available research into routine ultrasound during EARLY pregnancy showed they may have the benefits of enabling the caregiver to assess the baby's due date if the woman is unsure and identify multiple pregnancies earlier as well as detecting some abnormalities in a few unborn babies at a time when termination of the pregnancy is possible. However, other benefits are less clear and the physical risks are not well known, as well as the risk of terminating a healthy baby because the ultrasonographer incorrectly diagnosed an abnormality. (Neilson 2002).
    Meta-analysis of all available research into routine ultrasound during LATE pregnancy and routine Doppler examinations during late pregnancy conclude that there is no evidence to suggest that they improve the health and well being of mothers or babies (Bricker et al 2002).

    NOTE:As mentioned previously, caregivers believe ultrasounds are safe, but this is not completely certain. The general consensus is that ultrasounds can be helpful if there is a medical reason to use them but the benefits of 'routine' ultrasounds has not been proven.
    Cost and effectiveness
    There is no doubt that ultrasounds can be extremely helpful if a pregnant woman is experiencing medical problems. However, in recent years the use of ultrasounds during pregnancy has increased dramatically, with caregivers ordering more 'routine' ultrasounds and parents being more inclined to request an ultrasound (for visual reassurance). Other factors that have contributed to this significant increase include concerns about litigation (for fear of not detecting an abnormal baby) and parents wanting a 'photo' of their unborn baby. It is the 'routine' use of ultrasound and its use for non-medical reasons (such as detecting the baby's sex or for emotional reassurance), that causes most debate.
    The definition of a valid routine test is:
    '...that it is capable or detecting health conditions which may place the baby and/or mother at risk and which would not necessarily have been detected by other means (such as physical examination or a blood test). The findings of a routine test should make it possible for subsequent interventions or management that will improve the baby's and/or mother's health and well-being.'
    So far, the routine use of ultrasound has not been proven and does not improve the health and well-being of mothers and babies. However, it has been shown to increase parental concerns for the remainder of the pregnancy (if a possible problem is detected) and often encourages caregivers to implement unnecessary interventions. (This is further discussed in concerns and worries.)
    Ultrasonography is now big business. In the 1970's only about 10 to 20% of pregnant women were being exposed to ultrasound, generally if a medical problem was suspected. By the late 1980's it become fairly accepted that nearly all pregnant women would have at least 1 routine ultrasound (usually at 18 to 20 weeks to screen for abnormalities) as well as additional ultrasounds if problems arose. An Australian Parents Survey in 1994 reported that 99.5% of pregnant women had had at least one ultrasound. In recent years, especially since the introduction of genetic testing (particularly nuchal translucency), it is not unusual for women to have 2, 3, 4 (or more) ultrasounds during their pregnancies. The concern now is that ultrasounds are definitely being overused and at great cost to the taxpayer.
    In Australia, more than 1/3 of maternity expenditure goes on pregnancy ultrasounds. During the financial year 1998-1999, the government (through Medicare) paid out $38.6 million for pregnancy ultrasounds (almost all of it on routine scanning). Compare this to $27.6 million on labour and birth care (including complex births, Caesareans and post natal care after the birth) and $30 million on pregnancy visits. This has prompted comments from critics that we spend more on taking photos of babies than delivering them! Similar trends are seen in the United States and Europe.
    From February 1st 2000, the Australian Federal government altered the Medicare rebate to only cover ultrasounds for 'clinically relevant reasons', allocating scans into 17 different categories with varying rebates, depending on the nature of the test. This was done in an effort to reign in excessive spending on ultrasound tests.

  4. #4
    ♥ BellyBelly's Creator ♥
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    Feb 2003
    Melbourne, Victoria, Australia, Australia


    As we all know, ultrasound is something that is of personal choice - it's not essential to have one for pregnancy care. Some say, why have one if they would never terminate anyway, where others want the peace of mind.

    Dr. Sarah Buckley has written an article I will upload for next month on Ultrasound. Ultrasound is not as bad for baby as a handheld doppler, which has constant streaming of waves - ultrasound has breaks to bounce back an image, but never the less, Sarah says:

    "In the years since then I have had three more unscanned babies, and have read many articles and research papers about ultrasound. Nothing I have read has made me reconsider my decision (not to scan). Although ultrasound may sometimes be useful when specific problems are suspected, my conclusion is that it is at best ineffective and at worse dangerous when used as a ‘screening tool’ for every pregnant woman and her baby."

    If you'd like more info, some good books are: ‘Which Tests for my Unborn Baby’ and ‘Prenatal Testing: Making Choices in Pregnancy’ which are both co-authored by Lachlan de Crespigny, an expert in this area, are highly recommended, along with ‘The Tentative Pregnancy’.
    Kelly xx

    Creator of, doula, writer and mother of three amazing children
    Author of Want To Be A Doula? Everything You Need To Know
    In 2015 I went Around The World + Kids!
    Forever grateful to my incredible Mod Team

  5. #5
    BellyBelly Member

    Feb 2005
    Mid North Coast NSW

    its an interesting topic, and to be honest, not one i have given much thought until now...


  6. #6
    BellyBelly Life Subscriber

    Jun 2005
    Blue Mountains

    I remember seeing a documentary once (quite a while ago) and they showed the baby shying away from the ultrasound, and on a documentary recently they said that once the baby can hear, it's possible they can hear the ultrasound in the womb.

    A friend of mine loved every ultrasound she had (she had them very regularly as she had twins), and said she would always go for weekly u/s just coz she loved seeing the baby. I dunno... I'm inclined to only have them if I need them. I'm expecting one at around 12 wks, and one around 18-20 weeks. Do they do more than that? or only if there's concerns about the baby?

  7. #7
    BellyBelly Member

    Mar 2005
    Limestone Coast, SA

    I had planned on not having any u/s at all, but now that I am pregnant I am reconsidering. If I do decide to have u/s I will only have one at 18-20wks. I don't really see a lot of point in me having one cause I've already said no to all the other tests they have offered and DH and I are not going to consider termination anyhow. I think it is definately a personal choice, however there is quite a lot of evidence to suggest u/s is less than beneficial for an unborn baby, as somebody previously mentioned unborn babes tend to really shy away from u/s. Goodluck in making your decision.

  8. #8
    Sun Nymph Guest

    I think its really important for the Mum to be properly informed about the limitations of Ultrasounds and the possibility of false positives and negatives. I have known of quite a few women who worried for the whole pregnancy about cysts on kidney or the brain, only for it to be normal when scanned after birth. On the other hand, an acquaintence of mine had a baby with Down syndrome and heart defects that were not picked up on ultrasound. She felt quite betrayed by this, understandably.
    I can accept that for some couples it is a way of starting the bonding process (particularly for Dad) and does provide some degree of reassurance. Also even if there was some abnormality, for some parents I guess they can start preparing themselves physically and emotionally if they decide to continue the pregnancy.
    A very personal decision about which parents have a right to be informed.