Too many ultrasounds a bad thing?

Hi
My sister (a midwife) has warned me that having too many ultrasounds can be harmful to the baby. I had a dating scan on the 7th Feb, then ended up having bleeding and cramping on the 14th so had another ultrasound on the 15th (everything okay) then was due for a dr appt on the 20th anyway and told them about the scare and subsequent ongoing minor spotting so she did a quick scan in the room to see the heartbeat. I am wanting to do the NT scan in 2-3 weeks but my sister is telling me that I should just wait until the 19 weeker. I've been told by my ob that I've got a low chance of Downs and that I could even get a false positive result on the NT scan, so maybe I should just hold off until the 19 week one.
What's the general concensus (sp?) on here? Only one of the ultrasounds was a longish one, the other two were quite quick (just checking)
Thanks in advance

I've had 2 dating scans (Because they couldn't find anything on the first one). The NT scan, the 19 week scan, a quick scan at the ob the other day and I am having another scan at 34 weeks.

This is my second bub and I do feel like I have had too many scans because with my first I only had 3 for the entire time. I wish I didn't have the dating scans but I am happy that I had the NT scan. But that's just me.

There was a thread about this a few months ago when it was in the media a bit.

i have had two scans two weeks apart, for medical reasons then 4 weeks later am having nt scan havn't heard anything bad about it... my second scan was like 2 minutes to check everything was ok... id def be interested to hear about this some more then?

Personally i don't think they are harmful to a baby cause if they are required then that's the priority. My baby has a hole in her heart and i also have a history of placenta abruption therefore i have scans fortnightly. I wasn't exactly comfortable with the huge amount of scans i'm having (and they are extensive, long scans) but i'm in very good hands, seeing well-reputed specialists so i trust that they are doing what's best for my baby.

rae - its good to hear that they have ordered them for you fortnightly because i mean they wouldn't so it if it could be of harm... or if the risk out weighed the means...

Marsden Wagner MD:
Ultrasound More Harm Than Good?


The ultrasound story begins in July 1955 when an obstetrician in Scotland, Ian Donald, borrowed an industrial ultrasound machine used to detect flaws in metal and tried it out on some tumours, which he had removed previously, using a beefsteak as the control. He discovered that different tumours produced different echoes. Soon Donald was using ultrasound not only for abdominal tumours in women but also on pregnant women. Articles surfaced in the medical journals, and its use quickly spread throughout the world.

The dissemination of ultrasound into clinical obstetrics is reflected in inappropriate statements made in the obstetrical literature regarding its appropriate use: "One of the lessons of history is, of course, that it repeats itself. The development of obstetric ultrasound thus mirrors the application to human pregnancy of diagnostic X rays. Both, within a few years of discovery, were being used to diagnose pregnancy and to measure the growth and normality of the fetus. In 1935 it was said that "antenatal work without the routine use of X-rays is no more justifiable than would be the treatment of fractures" (Reece 1935). In 1978: "It can be stated without qualification that modern obstetrics and gynecology cannot be practiced without the use of diagnostic ultrasound" (Hassani 1978). Two years later, it was said that "ultrasound is now no longer a diagnostic test applied to a few pregnancies regarded on clinical grounds as being at risk. It can now be used to screen all pregnancies and should be regarded as an integral part of antenatal care" (Campbell & Little 1980). On neither of these dates did evidence qualify the speakers to make these assertions.

It is not only doctors who have tried to promote ultrasound with statements that go beyond the scientific data. Commercial interests also have been actively promoting ultrasound, and not only to doctors and hospitals. As an example, an advertisement in a widely read Sunday newspaper (The Times, London) claimed: Toshiba decided to design a diagnostic piece of equipment that would be absolutely safe ... The name: Ultrasound. A consumer organization in Britain complained to the Advertising Standards Authority that Toshiba was making an untrue claim, and the complaint was upheld. In many countries, the commercial application of ultrasound scanning during pregnancy is widespread, offering "baby look" and "fun ultrasound" in order to "meet your baby" with photographs and home videos.

The extent to which medical practioners nevertheless followed such scientifically unjustified advice, and the degree to which this technology proliferated, can be illustrated by recent data from three countries. In France, in one year three million ultrasound examinations were done on 700,000 pregnant women --- an average of more than four scans per pregnancy. These examinations cost French taaxpayers more than all other therapeutic and diagnostic procedures done on these pregnant women. In Australia, where the health service pays for four routine scans, in one recent year billing for obstetrical ultrasound was $60 million in Australian dollars. A 1993 editorial in U.S.A. Today makes the following statement: "Baby's first picture --- a $200 sonogram shot in the womb --- is a nice addition to any family album. But are sonograms medically worth $1 billion of the nation's scarce health-care dollars? That's the question raised by a United States study released this week. It found the sonograms that doctors routinely perform on healthy pregnant women don't make any difference to the health of their babies".

After a technology has spread widely in clinical practice, the next step is for health policymakers to accept it as standard care financed by the offical health sector. Several European countries now have official policy for one or more routine ultrasound scans during pregnancy. For example, in 1980 the Maternity Care Guidelines in West Germany stated the right of each pregnant woman to be offered at least two ultrasound scans during pregnancy.. Austria quickly followed suit, approving two routine scans. Do the scientific data justify such widespread use and great coast of ultrasound scanning?

When is Ultrasound Helpful?
In assessing the effectiveness of ultrasound in pregnancy, it is essential to make the distinction between its selective use for specific indications and its routine use as a screening procedure. Essentially, ultrasound has proven valuable in a handful of specific situations in which the diagnosis "remains uncertain after clinical history has been ascertained and a physical examination has been performed". Yet, considering whether the benefits outweigh the costs of using ultrasound routinely, systematic medical research has not supported routine use.

One of the most common justifications given today for routine ultrasound scanning is to detect intrauterine growth retardation (IUGR). Many clinicians insist that ultrasound is the best method for the identification of this condition. In 1986, a professinal review of 83 scientific articles on ultrasound showed that "for intrauterine growth retardation detection, ultrasound should be performed only in a high-risk population". In other words, the hands of an experienced midwife or doctor feeling a pregnant woman's abdomen are as accurate as the ultrasound machine for detecting IUGR. The same conclusion was reached by a study in Sweden, comparing repeated measurement of the size of the uterus by a midwife with repeated ultrasonic meassurements of the head size of the fetus in 581 pregnancies. The report concludes: "Measurements of uterus size are more effective than ultrasonic measurements for the antenatal diagnosis of intrauterine growth retardation".

If doctors continue to try to detect IUGR with ultrasound, the result will be high false-positive rates. Studies show that even under ideal conditions, such as do not exist in most settings, it is likely that over half of the time a positive IUGR screening test using ultrasound is returned, the test is false, and the pregnancy is in fact normal. The implications of this are great for producing anxiety in the woman and the likelihgood of further unnecessary interventions.

There is another problem in screening for IUGR. One of the basic principles of screening is to screen only for conditions for which you can do something. At present, there is no treatment for IUGR, no way to slow up or stop the process of too-slow growth of the fetus and return it to normal. So it is hard to see how screening for IUGR could be expected to improve pregnancy outcome.

We are left with the conclusion that, with IUGR, we can only prevent a small amount of it using social interventions (nutrition and substance-abuse programs), are very inaccurate at diagnosing it, and have no treatment for it. If this is the present state of the art, there is no justification for clinicians using routine ultrasound during pregnancy for the management of IUGR. Its use should be limited to research on IUGR.

Once again it is interesting to look at what happened with the issue of safety of X rays during pregnancy. X rays were used on pregnant women for almost 50 years and assumed to be safe. In 1937, a standard textbook on antenatal care stated: "It has been frequently asked whether there is any danger to the life of the child by the passage of X rays through it; it can be said at once there is none if the examination is carried out by a competent radiologist or radiographer". A later edition of the same textbook stated: "It is now known that the unrestricted use of X rays through the fetus caused childhood cancer". This story illustrates the danger of assuming safety. In this regard, a statement from a 1978 textbook is relevant: "One of the great virtues of diagnostic ultrasound has been its apparent safety. At present energy levels, diagnostic ultrasound appears to be without injurious effect ... all the available evidence suggests that it is a very safe modality".

That ultrasound during pregnancy cannot be simply assumed to be harmless is suggested by good scientific work in Norway. By following up on children at age eight or nine born of mothers who had taken part in two controlled trials of routine ultrasound in pregnancy, they were able to show that routine ultrasonography was associated with a symptom of possible neurological problems".

With regard to the active scientific pursuit of safety, an editorial in Lancet, A British medical journal, says: "There have been no randomized controlled trials of adequate size to assess whether there are adverse effects on growth and development of children exposed in utero to ultrasound. Indeed, the necessary studies to ascertain safety may never be done, because of lack of interest in such research".

The safety issue is made more complicated by the problem of exposure conditions. Clearly, any bio-effects that might occur as a result of ultrasound would depend on the dose of ultrasound received by the fetus or woman. But there are no national or international standards for the output characteristics of ultrasound equipment. The result is the shocking situation described in a commentary in the British Journal of Obstetrics and Gynaecology, in which ultrasound machines in use on pregnant women range in output power from extremely high to extremely low, all with equal effect. The commentary reads, "If the machines with the lowest powers have been shown to be diagnostically adequate, how can one possibly justify exposing the patient to a dose 5,000 times greater?". It goes on to urge government guidelines on the outut of ultrasound equipment and for legislation making it mandatory for equipment manufacturers to state the output characteristics. As far as is known, this has not yet been done in any country.

Safety is also clearly related to the skill of the ultrasound operator. At present, there is no known training or certification for medical users of ultrasound apparatus in any country. In other words, the birth machine has no license test for its drivers.

Looking Ahead: Ultrasound and the Future
Although ultrasound is expensive, routine scanning is of doubtful usefulness, and the procedure has not yet been proved to be safe, this technology is widely used, and its use is increeasing rapidly without control. Nevertheless, health policy is slow to develop. No country is known to have developed policies with regard to standards for the machines, nor for the training and certification of the operators. A few industrialized countries have begun to respond to the data showing lack of effectiveness for routine scanning of all pregnant women. In the United States, for example, a consensus conference on diagnostic ultrasound imaging in pregnancy concluded that "the data on clinical effectiveness and safety do not allow recommendation for routine screening at this time; there is a need for multidisciplinary randomized controlled clinical trials for an adequate assessment".

Denmark, Sweden, and the United Kingdom have made similar statements against routine screening. The World Health Organisation (WHO), in an attemmpt to stimulate governments to develop policy on this issue, published the following statement:

"The World Health Organisation stresses that health technologies should be thoroughly evaluated prior to their widespread use. Ultrasound screening during pregnancy is now in widespread use without sufficient evaluation. Research has demonstrated its effectiveness for certain complications of pregnancy, but the published material does not justify the routine use of ultrasound in pregnant women. There is also insufficient information with regard to the safety of ultrasound use during pregnancy. There is as yet no comprehensive, mulitdisciplinary assessment of ultrasound use during pregnancy, including: clinical effectiveness, psychosocial effects, ethical considerations, legal implications, cost benefit, and safety.

"WHO strongly endorses the principle of informed choice with regard to technology use. The health-care providers have the moral responsibility: fully to inform the public about what is known and not known about ultrasound scanning during pregnancy; and fully to inform each woman prior to an ultrasound examination as to the clinical indication for ultrasound, its hoped-for benefit, its potential risk, and alternative available, if any."

This statement, sadly, is as relevant today. During the 1980s and early 1990s, a number of us were raising questions about both the effectiveness and safety of fetal scanning. Our voice of caution, however, was like a cry in the wilderness as the technology proliferated. Then, during the course of one month in late 1993, two landmark scientific papers were published.

The first paper, a largely randomized trial of the effectiveness of routine prenatal ultrasound screening, studied the outcome of more than 15,000 pregnant women who either received two routine scans at 15 to 22 weeks and 31 to 35 weeks, or were scanned only for medical indications. Results showed that the mean number of sonograms in the ultrasound group was 2.2 and in the control group (for indication only) was 0.6. The rate of adverse outcome (fetal death, neonatal death, neonatal morbidity), as well as the rate of preterm delivery and distribution of birth weights, was the same for both groups. In addition, in the author's words: "The ultrasonic detection of congenital abnormalities has no effect on perinatal outcome". At last we have a randomized clinical trial of sufficient size to conclude that there is no value to routine scanning during pregnancy.

The second landmark paper, also a randomized controlled trial, looked at the safety of repeated prenatal ultrasound imaging. While the original purpose of the trial was hopefully to demonstrate the safety of repeated scanning, the results were the opposite. From 2,834 pregnant women, 1,415 received ultrasound imaging at 18,24, 28, 34 and 38 weeks gestation (intensive group) while the other 1,419 received single ultrasound imaging at 18 weeks (regular group). The only difference between the two groups was significantly higher (one-third more) intrauterine growth retardation in the intensive group. This important and serious finding prompted the authors to state: "It would seem prudent to limit ultrasound examinations of the fetus to those cases in which the information is likely to be of clinical importance". Ironically, it is now likely that ultrasound may lead to the very condition, IUGR, that it has for so long claimed to be effective in detecting.

Although we now have sufficient scientific data to be able to say that routine prenatal ultrasound scanning has no effectiveness and may very well carry risks, it would be naive to think that routine use will not continue.

Unfortunately, medical doctors are inadequately educated in the basics of scientific method. It will be a struggle to close the gap between this new scientific data and clinical practice.

Ultrasound: Weighing the Propaganda Against the Facts
by Beverley Lawrence Beech
© 1999 Midwifery Today, Inc. All rights reserved
The use of ultrasound in antenatal care is big business, and in any big business marketing is all-important. As a result of decades of enthusiastic marketing, women believe they can ensure the well-being of their babies by reporting for an early ultrasound scan and that early detection of a problem is beneficial for these babies. That is not necessarily so, and there are a number of studies which show that early detection can be harmful.
In response to women’s desire for information about the implications of routine ultrasound examinations, Jean Robinson and I wrote the book Ultrasound? Unsound, in which we reviewed the research evidence and drew attention to some of the hazards (Beech and Robinson, 1996). But since then more evidence has accumulated. For example:
Miscarriage
It is ironic that women who have had previous miscarriages often have additional ultrasound examinations in order to "reassure" them that their baby is developing properly. Few are told of the risks of miscarriage or premature labour or birth.
Obstetricians in Michigan (Lorenz et al., 1990) studied fifty-seven women who were at risk of giving birth prematurely. Half were given a weekly ultrasound examination; the rest had pelvic examinations. Preterm labour was more than doubled in the ultrasound group–52 percent–compared with 25 percent in the controls. Although the numbers were small the difference was unlikely to have emerged by chance.
A large randomised controlled trial from Helsinki (Saari-Kemppainen et al., 1990) randomly divided over 9,000 women into a group who were scanned at sixteen to twenty weeks compared with those who were not. It revealed twenty miscarriages after sixteen to twenty weeks in the screened group and none in the controls.
A later study in London (Davies et al., 1993) randomised 2,475 women to routine Doppler ultrasound examination of the umbilical and uterine arteries at nineteen to twenty-two weeks and thirty-two weeks compared with women who received standard care without Doppler ultrasound. There were sixteen perinatal deaths of normally formed infants in the Doppler group compared with four in the standard care group.
It is not only pregnant patients who are at risk, however. Physiotherapists use ultrasound to treat a number of conditions. A study done in Helsinki (Taskinen et al., 1990) found that if the physiotherapist was pregnant, handling ultrasound equipment for at least twenty hours a week significantly increased the risk of spontaneous abortion. Also, the risk of spontaneous abortions occurring after the tenth week was significantly increased for deep heat therapies given for more than five hours a week and ultrasound more than ten hours a week.
Miscarriage
It is ironic that women who have had previous miscarriages often have additional ultrasound examinations in order to "reassure" them that their baby is developing properly. Few are told of the risks of miscarriage or premature labour or birth.
Obstetricians in Michigan (Lorenz et al., 1990) studied fifty-seven women who were at risk of giving birth prematurely. Half were given a weekly ultrasound examination; the rest had pelvic examinations. Preterm labour was more than doubled in the ultrasound group–52 percent–compared with 25 percent in the controls. Although the numbers were small the difference was unlikely to have emerged by chance.
A large randomised controlled trial from Helsinki (Saari-Kemppainen et al., 1990) randomly divided over 9,000 women into a group who were scanned at sixteen to twenty weeks compared with those who were not. It revealed twenty miscarriages after sixteen to twenty weeks in the screened group and none in the controls.
A later study in London (Davies et al., 1993) randomised 2,475 women to routine Doppler ultrasound examination of the umbilical and uterine arteries at nineteen to twenty-two weeks and thirty-two weeks compared with women who received standard care without Doppler ultrasound. There were sixteen perinatal deaths of normally formed infants in the Doppler group compared with four in the standard care group.
It is not only pregnant patients who are at risk, however. Physiotherapists use ultrasound to treat a number of conditions. A study done in Helsinki (Taskinen et al., 1990) found that if the physiotherapist was pregnant, handling ultrasound equipment for at least twenty hours a week significantly increased the risk of spontaneous abortion. Also, the risk of spontaneous abortions occurring after the tenth week was significantly increased for deep heat therapies given for more than five hours a week and ultrasound more than ten hours a week.
Miscarriage
It is ironic that women who have had previous miscarriages often have additional ultrasound examinations in order to "reassure" them that their baby is developing properly. Few are told of the risks of miscarriage or premature labour or birth.
Obstetricians in Michigan (Lorenz et al., 1990) studied fifty-seven women who were at risk of giving birth prematurely. Half were given a weekly ultrasound examination; the rest had pelvic examinations. Preterm labour was more than doubled in the ultrasound group–52 percent–compared with 25 percent in the controls. Although the numbers were small the difference was unlikely to have emerged by chance.
A large randomised controlled trial from Helsinki (Saari-Kemppainen et al., 1990) randomly divided over 9,000 women into a group who were scanned at sixteen to twenty weeks compared with those who were not. It revealed twenty miscarriages after sixteen to twenty weeks in the screened group and none in the controls.
A later study in London (Davies et al., 1993) randomised 2,475 women to routine Doppler ultrasound examination of the umbilical and uterine arteries at nineteen to twenty-two weeks and thirty-two weeks compared with women who received standard care without Doppler ultrasound. There were sixteen perinatal deaths of normally formed infants in the Doppler group compared with four in the standard care group.
It is not only pregnant patients who are at risk, however. Physiotherapists use ultrasound to treat a number of conditions. A study done in Helsinki (Taskinen et al., 1990) found that if the physiotherapist was pregnant, handling ultrasound equipment for at least twenty hours a week significantly increased the risk of spontaneous abortion. Also, the risk of spontaneous abortions occurring after the tenth week was significantly increased for deep heat therapies given for more than five hours a week and ultrasound more than ten hours a week.
Diagnosis of placental praevia
The Saari-Kemppainen study also revealed the lack of value in early diagnosis of placenta praevia. Of the 4,000 women who were scanned at sixteen to twenty weeks, 250 were diagnosed as having placenta praevia. When it came to delivery, there were only four. Interestingly, in the unscanned group there were also four women found at delivery to have this condition. All the women were given caesarean sections and there was no difference in outcomes between the babies. Indeed, there are no studies which demonstrate that early detection of placenta praevia improves the outcome for either the mother or the baby. The researchers did not investigate the possible effects on the 246 women who presumably spent their pregnancies worrying about having to undergo a caesarean section and the possibility of a sudden haemorrhage.
Babies with serious defects
Almost all babies receive a dose of ultrasound, but even at the best centres wide variations occur in detection rates for babies with major heart abnormalities. Both national and international detection rates differ widely in published studies (which are usually undertaken in centres of excellence), but the majority of mothers will be exposed to older machines in ordinary hospitals and clinics. The skill of the operators will vary (everybody has to learn sometime), but even with the best machines and the best operators misdiagnoses occur. A study from Oslo (Skari et al., 1998) looked at how many babies born with serious defects had been diagnosed by antenatal scans, and whether the early diagnosis made any difference to the outcomes. Women in Norway have a scan at seventeen to twenty-one weeks done by trained midwives, who refer to obstetricians if an abnormality is suspected.
In nineteen months, thirty-six babies were referred from a population of 2.5 million. They had diaphragmatic hernias, abdominal wall defects, bladder extrophy or meningomyelocele. Only thirteen of the thirty-six defects had been detected before birth (36 percent). They found that only two of eight congenital diaphragmatic hernias were picked up on ultrasound, half the cases of abdominal wall defects (six out of twelve), 38 percent of the meningomyelocele (five out of thirteen) and none of the three cases of bladder extroversion. The mothers had an average of five scans (from one to fourteen); those in whose cases abnormality was detected had an average of seven.
Three out of the thirteen babies diagnosed antenatally died. There was one death in the twenty-three undiagnosed. All thirteen babies with antenatal diagnosis were delivered by caesarean. Nineteen of the twenty-three undiagnosed babies had an uncomplicated vaginal delivery. The diagnosed babies had lower birth weight and two weeks shorter gestation. Although the babies with pre-diagnosed abdominal wall defects received surgery more quickly (four hours versus thirteen hours), the outcomes were the same in both groups. Although small, this is an important study.
Pregnant women often automatically assume that antenatal detection of serious problems in the baby means that lives will be saved or illness reduced. Knowing about the problem in advance did not benefit these babies; more of them died. They got delivered sooner, when they were smaller, a choice that could have long-term effects. All twelve babies with abdominal wall defects survived. But for the six detected on the scan, their length of hospital stay was longer and they spent longer on ventilators, though the numbers are too small to be significant. They were operated on sooner (four hours rather than thirteen hours) but the outcomes were the same.
Growth Retarded Babies
One of the promises held out by antenatal scanning is that obstetricians will be able to identify the baby with problems and do something to help it. A German study from Wiesbaden hospital (Jahn et al., 1998) found that out of 2,378 pregnancies only fifty-eight of 183 growth retarded babies were diagnosed before birth. Forty-five fetuses were wrongly diagnosed as being growth retarded when they were not. Only twenty-eight of the seventy-two severely growth-retarded babies were detected before birth despite the mothers having an average of 4.7 scans.
The babies diagnosed as small were much more likely to be delivered by caesarean - 44.3 percent compared with 17.4 percent for babies who were not small for dates. If the baby actually had intrauterine growth retardation (IUGR) the section rate varied hugely according to whether it was diagnosed before birth (74.1 percent sectioned) or not (30.4 percent).
So what difference did diagnosis make to the outcome for the baby? Pre-term delivery was five times more frequent in those whose IUGR was diagnosed before birth than those who were not. The average diagnosed pregnancy was two to three weeks shorter than the undiagnosed one. The admission rate to intensive care was three times higher for the diagnosed babies.
The long-term emotional impact
The effects of screening on both parents can be profound. For example, women waiting for the results of tests try not to love the baby in case they have to part with it. The medical literature has little to say about the human costs of misdiagnosis unless the baby was mistakenly aborted, and even then it tends to focus on legal action. However, a letter in the British Medical Journal revealed how a diagnosis of a minor anomaly can have serious long-term implications for the family:
A couple was referred for amniocentesis during the wife’s second pregnancy on the grounds of maternal age, thirty-five years, and anxiety. Their three-year-old son played happily during the consultation. When his wife and son had left the room after the procedure the husband confided that they had opted for amniocentesis to avoid having another "brain damaged" child. On questioning it became apparent that an ultrasound examination before their son’s birth had shown a choroid plexus cyst. Despite having a healthy child, the husband remained convinced that this cyst could cause his son to be disabled. (Mason and Baillie, 1997).
Evaluating the risks
When ultrasound was first developed researchers suggested that "the possibility of hazard should be kept under constant review" (Donald, 1980), and they said that it would never be used on babies under three months. However, as soon as vaginal probe ultrasound was developed, which could get good pictures in early pregnancies (and get nearer to the baby giving it a bigger dose), this initial caution was ignored.
Research by Lieberskind revealed "the persistence of abnormal behaviour . . . in cells exposed to a single dose diagnostic ultrasound ten generations after insonation." She concluded, "If germ cells were . . . involved, the effects might not become apparent until the next generation" (Lieberskind, 1979). When asked what problems should be looked for in human studies, she suggested: "Subtle ones. I’d look for possible behavioural changes, in reflexes, IQ, attention span" (Bolsen, 1982).
Because ultrasound has been developed rapidly without proper evaluation it is extremely difficult to prove that ultrasound exposure causes subtle effects. After all, it took over ten years to prove that the gross abnormalities found in some newborn babies were caused by thalidomide. However, there are a number of ultrasound studies which raise serious questions that still have to be addressed.
The first evidence we saw of possible damage to humans came in 1984 when American obstetricians published a follow-up study of children, aged seven to twelve years born in three different hospitals in Florida and Denver, who had been exposed to ultrasound in the womb (Stark et al., 1984). Compared with a control group of children who had not been exposed they were more likely to have dyslexia and to have been admitted to hospital during their childhood, but no other differences were found.
In 1993 a study in Calgary, Alberta which examined the antenatal records of seventy-two children with delayed speech of unknown cause were compared with those of 142 controls who were similar in sex, date of birth and birth order within the family. The children were similar in social class, birthweight and length of pregnancy. The children with speech problems were twice as likely as controls to have been exposed to ultrasound in the womb. Sixty-one percent of cases and only 37 percent of controls had had at least one exposure.
A Norwegian study (Salvesen, 1993) showed an increase in left handedness, but no increase in dyslexia. While the increase in left handedness was not large, it does suggest that ultrasound has an effect on the development of the brain. It should be noted, however, that the scanners used in this study emitted very low doses of ultrasound–lower than exposures from many machines nowadays–the women had only two exposures, and it was real time, not Doppler, a more powerful form of ultrasound.
Assessing the risks
"Present day ultrasonic diagnostic machines use such small levels of energy that they would appear to be safe, but the possibility must never be lost sight of that there may be safety threshold levels possibly different for different tissues, and that with the development of more powerful and sophisticated apparatus these may yet be transgressed" (Donald, 1979).
Donald’s foresight was remarkable. The machines in use today are far more powerful than the machines used a decade or more ago, and new variants are being developed all the time.
There has been inadequate research into the potential long-term effects. Measuring the outcome of any intervention in pregnancy is very complicated because there are so many things to look at. Intelligence, personality, growth, sight, hearing, susceptibility to infection, allergies and subsequent fertility are but a few issues which, if affected, could have serious long-term implications, quite apart from the numbers of babies who have a false positive or false negative diagnosis. Because a baby grows rapidly, exposing it to ultrasound at eight weeks can have different effects than exposure at, for example, ten, eighteen or twenty-four weeks (this is one of the reasons the effects of potential exposure are so difficult to study). Women are now exposed to so many different types of ultrasound: Doppler scans, real-time imaging, triple scans, external fetal heart-rate monitors, hand held fetal monitors. Unlike drugs, whereby every new drug must be tested, the rapid development of each new variation of ultrasound machine has not been accompanied by similar careful evaluation by controlled, large-scale trials.
Despite decades of ultrasonic investigation, no one can demonstrate whether ultrasound exposure has an adverse effect at a particular gestation, whether the effects are cumulative or whether it is related to the output of a particular machine or the length of the examination. How many exposures are too many? What is the mechanism by which growth is affected? A large-scale study (Newnham et al., 1991) showed decreased birthweight, although a later study suggested the babies soon make up the deficit. It should not be forgotten, however, that numerous studies on rats, mice and monkeys over the years have found reduced fetal weight in babies that had ultrasound in the womb compared with controls. Nor should it be forgotten that in the monkey studies (Tarantal et al., 1993) the ultrasound babies sat or lay around the bottom of the cage, whereas the little control monkeys were up to the usual monkey tricks. Long-term follow up of the monkeys has not been reported. Do they reproduce as successfully as the controls? And, as Jean Robinson has noted: "Monkeys do not learn to read, write, multiply, sing opera, or play the violin." Human children do, and perhaps we should consider seriously whether the huge increases in children with dyslexia and learning difficulties are a direct result of ultrasound exposure in the womb. Furthermore, when a woman is scanned her baby’s ovaries are also scanned. So if the woman had seven scans during her pregnancy, when her pregnant daughter eventually presents years later at the antenatal clinic, her developing baby will already have had seven scans. Do women really know what they consent to when they rush to hospital to have their first ultrasound scan, then trustingly agree to further scans?

I have had 6 u/s during this pg, am currently just over 24 weeks. I had so many due to my history of m/c and my fear that this one wasn't gonna stick, so OBS did the first three (at 7, 9 & 11 weeks) and I had another 3 at the imaging centre (12 weeks & 2 at 20 weeks).
I have had no bleeding or any othe issues, except for an irregular h/b at the 20 week one, and went back a week later to see if it had fixed itself, which it had.

I had about 20 scans with my last pregnancy.
I had them at 6wks, 8wks, 12wks, 15wks,19wks, 24wks and then every week from 26wks till 37wks and a couple of quick scans in between as well.

I don't think they are harmful.

I had scans done at 7, 10, 12,15,17,19,23,26,29,31,34 WOW 11 and that isnt counting the ones done at my Obst rooms. I also had to have surgery at 13 weeks with a general anasaetic so my poor girl got the lot.
She is fine and without the scans it is more than likely she wouldnt be
Bec

I've had a lot of scans done, both during this PG and my previous one due to my history of m/c and autoimmune issues (I'd say over 10 scans each time). I have a quick (like, 1 minute) scan done at every OB appt and I have very regular appts. And yes, most of the u/s I've had done have been to 'reassure' me that everything is still going well with the baby. After 2 m/c, PG can be a stressful time for me and stress tends to trigger one of my autoimmune conditions which means a not so happy end to the PG. Having regular scans has been of huge benefit to me.

IMO if you need to a lot of scans then have them and don't worry about it. If you don't feel that you really need a scan done and are concerned about any risks then don't do it. Do what feels right for you.

Angel, I hear your concerns and understand why the doc wants to reassure you as much as possible but was it not an option to use a dopplar to hear the baby's heart for a few seconds rather than ultrasound?

I personally love seeing my little guy wriggling around in there and am soooo looking forward to my next scan on the 8th of march.

Here you get 2 scans, 18 weeks and 32 weeks. I also had a very quick one at 14 weeks as I had a tummy flu and was throwing up and was stressed out about heaving so hard I'd damage something, so the doc did a quick one to check that the heart was pumping away happily and that the placenta was looking good....all was peachy!

The only thing I've really heard that it can affect is lefthandedness. If you have multiple ultrasounds, you apparently have a higher chance of having a left handed child!

Of course I've heard of the miscarriage risk too, but at 33 weeks, I'm a little beyond that risk area!

Adele, you can see things are going well via u/s a lot sooner than you can hear a HB with a doppler. Also with an u/s you can keep an eye on placental function.

With my last pg, I had 7 (6, 7.5, 9.5, 13, 14, 19, 23), 3 by obgyn who's mach is no-where near as powerful as the hospital & sonographer's machines. My obgyn, whom my GP recommended as highly experienced & 1st on her list, said the only thing they have found with lots & lots of u/sounds is a possible 1-3% decrease in birth weight. With this one, I've had 2 & next one is in 2.5wks. I had the NT scan on both occasions, as the older u get the higher the downs & trisomy risk. I'm glad I did coz my stats after U/S were extremely low compared to a higher risk b4 hand (results in www - milestones). I also used my doppler 1-4 times/mth, which is much lower in power/strength again.

I never thought about the impact that a scan can have on the baby until Kelly posted a few articles about it. Now I sort of think twice about it. I only ever had 3 at the most during pg (with Lindsay) and have had one so far this pg and will have the final one at 20wks unless there is a reason to have another.

When I had my scan with this baby at 10wks, it wriggled and moved about heaps and I immediately thought about the articles and that baby's don't like the scans at all and in fact they tend to move away from it. I liken it to tapping a fish tank - with the soundwaves travelling through the water and being deafening to fish kwim? Not that the u/s is deafening to a baby, but rather that they don't like the 'soundwaves' they feel in the womb. And how many times have you heard someone say that as soon as the paddle was put on the baby they started moving? certainly food for thought anyway.

But absolutely if you are high risk etc, then obviously they have their place and you will put the benefits of knowing the baby's health is OK before the small risks that are possible.

ETA - Found this article posted by Kelly (BellyBelly) back in September last year, it is a bit different to Alan's articles.

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Pregnant women warned over ultrasounds
By Tamara McLean
September 20, 2006 02:58pm
Article from: AAP


Quote:
PREGNANT women should not expose their unborn babies to unnecessary ultrasound scans because too little is known about the dangers, an academic has warned.

Karen Pollard, a medical imaging lecturer at Charles Sturt University, says mothers-to-be are now routinely getting the scans at least once during pregnancy.

While they are not necessarily unsafe, the dangers of the procedure have never really been established, said Ms Pollard, who will lecture publicly on the topic tomorrow.

"If there's a medical reason to have an ultrasound, have it, but if its purely for curiosity, don't," she said. Old studies showing that ultrasound was safe were no longer relevant because today's equipment had far greater exposure intensity than earlier scans, Ms Pollard said.

"What we do know about intensities at that level is if you were to ultrasound a cyst, you may see acoustic streaming, that is, the fluid in the cyst starts to move around," she said.

"If it can do that to the fluid inside a cyst at relatively short exposure times, what is it doing to a 12-week foetus which is at a stage of development where cell division is happening and the organs are forming?

"I have some concerns." Ultrasound scans used to be performed at about 18 to 20 weeks through the mother's abdomen, she said. But these days it has become routine to have an ultrasound through the vagina at 12 weeks, "so the ultrasound probe is right up against the cervix, right next to the foetus."

"If someone asks is it safe, the GP may say 'yes' whereas the sonographer will say 'well we think so, as far as we know'," Ms Pollard said.

A ten-year Western Australia study showed that babies who were scanned a lot had significant growth retardation. Ms Pollard said while these babies were probably being scanned due to worries about their growth rate, the ultrasound may also have affected their size.

"We just don't know," she said. Another study from Sweden has linked ultrasound to brain damage causing left-handedness in babies.

But the Royal Australian and New Zealand College of Obstetricians and Gynaecologists has repeatedly said no clinical studies have shown any risk to unborn children from the scans.

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Thanks for everyones help and opinions. I'm in a very low risk category for NT and like I said, have already had 3 scans. We've decided against the NT scan but at my next appt, I'm going to ask for a quick peek to check on hb. I think that the less scans or intensity of scans the better. If they were to find a medical reason as to why I need more scans then I will take my docs word for it and do them. But at the moment, any more scans that I have will be purely for curiositys sake.
Thanks again and H&H pregnancies and births to us all