Pregnancy these days can be a minefield of medical examination and testing, from the time you first do the home pregnancy test until the moment baby takes his or her first breath, and even after then. Most women accept the barrage of testing without question, feeling that the more information they can have, the better, whereas others opt out of some or all of them entirely. However, one thing many women don’t feel comfortable skipping are routine ultrasound scans.
In New Zealand, the average woman will undergo three different scans during her pregnancy as standard practice: the early ‘dating’ scan, the 12 week scan to check for risk of Down Syndrome and other congenital abnormalities that may be detectable by that stage, and the anatomy scan performed around 20 weeks to look for any abnormalities in the baby’s development. Many people will also use this one to find out the sex of the baby. In certain circumstances, some women will be offered further growth scans if they’re deemed at risk of a too-small or too-large baby, or if conditions such as placenta praevia are detected, and yet more if the pregnancy proceeds post-dates to ensure the baby is healthy and happy.
For many people, these peeks into the womb and the hidden world of the unborn child are gleefully anticipated as one of the most exciting milestones of pregnancy, bringing joy and making women feel more ‘connected’ and ‘bonded’ to their growing babe. An entire industry has sprung up in recent years around fetal scanning, with a growing number of couples opting for extra 3D and 4D scans at private clinics – the ‘clay model’ images providing a startling ‘preview’ of what their baby looks like at that moment in time. Facebook and other social media sites are often awash with images expectant parents put up to share their growing baby with the world.
So with all this in mind, we must ask the question: how safe is ultrasound really? And how necessary?
The use of ultrasound has increased enormously since its introduction in the 1960s, with technology ever-improving and evolving. The vast majority of women will undergo at least one scan during pregnancy, generally aimed at ensuring the developing foetus is growing normally and is free from the myriad congenital abnormalities that can be viewed by sonography. Generally the view is that the sooner you know about something, the easier it will be to treat and the better the outcome. The use of first trimester ultrasound is also popular for estimating the baby’s due date, which many women find particularly useful if they’re unsure of their dates, have an irregular menstrual cycle, or find themselves unexpectedly pregnant and aren’t sure of when conception could have happened.
However, there is also evidence that for all the good they can potentially do, ultrasounds could possibly be harmful to the growing fetus, being linked in recent years to various neurological problems, intra-uterine growth restriction, and other health problems, and the scans may not even make any significant difference to the outcomes for those infants in whom a congenital abnormality is detected.
There are a number of issues with ultrasound that many women may not be aware of, each of which could be the subject of an entire story – please consider this a mere overview!
Firstly, the level of radiation exposure and dosage of ultrasound used varies across equipment, meaning broad differences in potential levels a fetus may be exposed to. As technology has improved and the detail able to be visualized on machinery has grown, so too have the levels of radiation babies are exposed to in utero – with 3D and 4D technology posing the greatest risks, alongside the hand-held dopplers used at many routine antenatal visits to listen to baby’s heartbeat. Many people are unaware that this is a form of pulsed ultrasound with much higher output than other forms, and that there are non-radiation alternatives available on request such as wooden pinard horns (fetoscopes).
It is known that ultrasound can cause thermal changes, where the waves are absorbed by some tissue which causes localized heating (in bone especially, causing potential risks to the brain via the skull), and cavitation, where the ultrasound wave connects with tiny gas bubbles. This can cause them to move, expand, or collapse, resulting in changes at a cellular level in the developing bone and other tissue, the outcome of which has not been properly studied. There are further studies linking ultrasound in pregnancy to left-handedness and to increased risk of dyslexia, and more recently the increased use of routine ultrasound has been connected to the ever-increasing epidemic of autism and Autism Spectrum Disorders, following worrying studies of brain development in mice. As well as all this, and despite the use of ultrasound to monitor fetal growth, there are links between ultrasound and prematurity, and ultrasound and Intra-Uterine Growth Restriction.
Whilst much of this research is fairly preliminary, and some has not been able to be replicated in later trials, there are some very persistent findings that do appear valid – the connection between ultrasound and left-handedness in particular. If indeed the scans during pregnancy are causing changes in the developing brain that lead to this outcome, it begs the question of what other changes are taking place that we aren’t aware of as yet?
There are also issues to do with accuracy that can arise when things are apparently detected by ultrasound, that are worth considering prior to undergoing the scan. What happens if, for example, a woman experiences bleeding early in pregnancy and is told after examination that no heartbeat is detected, and termination is recommended as the fetus has died. Many women will agree to a termination to ‘speed things along’, yet there are plenty of reports of women who have decided instead to allow the body to abort naturally and gone on to continue the pregnancy to term, finding that the fetus was still alive, viable, and healthy.
Likewise, if the nuchal translucency scan finds an increased chance of Down Syndrome, are you likely to want to abort the pregnancy? To go on to more invasive and potentially harmful assessment such as amniocentesis? Or to continue the pregnancy as normal and not worry about whether or not baby does indeed have such a difference?
Then there’s the question of whether or not scans are indeed always accurate for detection of growth restriction and babies that are deemed too big or small, which can often lead to increased rates of interventions such as induction or caesarian. Studies have shown that cases of genuine IUGR are missed around 30% of the time, whereas around half of all cases ‘diagnosed’ by ultrasound turn out to not be IUGR at all. In other words, often things are missed, or the scans have ‘got it wrong’, with much depending on the sonographer and their interpretation of the findings and measurements.
There are also studies showing that, despite the prevailing belief that if you find an anomaly early by way of ultrasound, it can improve the outcome for baby during and after birth, there is no difference in perinatal mortality or other outcomes between things being picked up antenatally or postnatally. The WHO note that even when abnormalities are detected, no reduction in adverse outcomes can be found.
Of course, when medically indicated, scans can be extremely useful and have saved lives – there is no doubt that there are times where the possible benefits of knowing something or being accurately monitored for a complication that has arisen likely outweigh any potential risks. In these cases, ultrasound can be a lifesaving intervention and something we can certainly be grateful to have access to in this country. The question is whether or not the targeted screening for at-risk women justifies the routine screening of all women throughout pregnancy, given the possibility of risk to the growing baby.
So what are your rights when it comes to scans in pregnancy?
There are reports from around New Zealand of mothers requesting brief scans of limited duration, or opting out of all but one scan, and being told by the sonographer that they are unable to perform such a brief examination and are required to ‘tick off a list of boxes’, despite protests from the woman or her family. These women are then bullied into scans that are of longer duration than they want, causing distress and feelings of anxiety or guilt as a result, despite ultrasound not being compulsory and this being a breach of informed consent laws. It is worth having a conversation with the examiner before going in to the exam room, explaining what your wishes are and agreeing to them together prior to the beginning of the scan. If the person is unwilling to honour your request for a shorter exam, find somebody else. And if you feel at all coerced into a scan against your wishes, you are well within your rights to lay a complaint with the Health and Disability Commissioner.
Ultimately, although it has clear benefits when medically indicated, ultrasound is not something that has ever been proven safe, despite its widespread and routine use in pregnancy around the world for decades, and it has been linked to numerous potential adverse health events in later life. You are well within your rights to decline any or all scans in pregnancy – or to agree to them all. Ultrasound is not compulsory, and the onus is on the individual woman to discuss any concerns with her LMC (Lead Maternity Carer) and to do her own research, and decide how she would like to proceed. Whether this be with all routine scans, or some, or none. While it can be nice to see an image of your growing child, one must ask whether it is always worth the pretty picture.
Erin Young is a Naturopath, Nutritionist and Medical Herbalist at Apothecare Natural Health. She has experience in print media as a journalist and is currently writing a book about parenting naturally while enjoying being a parent to her wee boy.