Getting your baby’s ultrasound is an exciting time for parents, seeing baby move, seeing the little the heart beat beating, feet and hands moving! The little one growing inside you is such a miracle! And don’t forget to take the ultrasound pictures home to show everyone and save as a keepsake! Such a happy time!! So I apologize if I’m bursting your happy bubble with this blog post with the not- so- happy-research upon the safety of such screening. Ultrasounds, and Doppler electronic fetal monitoring (you know the ones your OB or midwife uses at each of your appointments to hear babies heartbeat) have not been proven safe, but they also hasn’t been proven unsafe, leading many parents and doctors to be skeptical about the use of in-utero ultrasounds and Doppler electronic fetal monitoring devices.
My own ultrasound appointments and readings into the safety of ultrasounds has led me to do more research into this topic. You will not get a conclusive answer here, (nor will you in any research studies) but I’m hoping that from the research I discuss, will help you discuss your options with your midwife or OB before deciding to have an ultrasound or use the Doppler, both of which have been used so routinely no one even questions the safety of such devices, and most doctors will tell you they are safe when this hasn’t been conclusively proven.
Research and studies point out health issues and abnormalities related to ultrasound & Doppler scans:
- Problems can occur for the fetus with sound and heat, and because an ultrasound is a form of energy, even the small amount of heat that is produced during the scan “can heat tissues slightly, and in some cases, it can also produce very small bubbles (cavitation) in some tissues.” (1)
- The long-term effects of tissue heating and cavitation aren’t known, but the FDA warns that ultrasounds should only be done when there is a medical need to do so. Another study reported that the heated tissue endured by the fetus when exposed to ultrasound and Doppler monitor “can produce significant heating of the fetal brain; the rate of heating near bone is rapid, with approximately 75% of the maximum heating occurring within 30 seconds” and that “the threshold for irreversible damage in the developing embryo and fetal brain is exceeded when a temperature increase of 4°C is maintained for 5 minutes.” (2) If damage can occur within a 5 minute ultrasound, what about the ultrasounds that take 30 minutes or more?
- Additionally, one point that I have read in many books points to research conducted in 2001 which concluded that the ultrasound aimed directly at miniature headphones which were placed in a woman’s uterus recorded sound as loud “as a subway train coming into the station” (3)
The question then is: What are the resulting biological effects and damage from such heating and sound experienced by fetus?
- No one can be certain, but it’s said that the temperature increase can cause significant damage to the fetus’s central nervous system (4) as has been reported in animal studies which resulted in birth defects in offspring.
- A summary of ultrasound effects published in 1982 by The World Health Organization reported “animal studies suggest neurological, behavioral, developmental, immunological, hematological changes and reduced fetal weight can result from exposure to ultrasound.” (5)
- Additionally, questions have been raised possibly linking to the increasing rates of autism in children, and increased birth defects involving the heart, genitals and urinary tract in babies to the time spent by the sonographer checking the sex of the fetus, and checking the heart development. The specific causes of these conditions are unknown, leaving us with more questions than we have answers for.
What happens during a 1st trimester ultrasound? (sometimes called a dating ultrasound)
- Check that baby is developing normally
- Check where the placenta is in the uterus (my sonographer didn’t do this, and had I known, I would have asked her to make sure to check to avoid having the 18-22 week scan)
- Confirm your due date
- Confirm the number of babies in the womb
Most practitioners will send you to get an 18-22 ultrasound as a routine, but you do not have to do it, the decision is up to you. If you are not having a high risk pregnancy, and your first ultrasound already detected where your placenta was growing, (and determined it wasn’t placenta previa) you may not need to have the 18-22 week ultrasound. It’s important to have an open discussion with your midwife/OB about what information will be gathered during the ultrasound and whether it will affect your current daily activities, or your birth plan, and or if there is anything that can be done to remedy the situation should there be any concerns.
Personally, the only reason I went for my 18—22 week ultrasound was to find out where the placenta was as the first ultrasound I had at 8 weeks didn’t report it. (A low lying placenta called placenta previa is where the placenta partially or wholly blocks the neck of the uterus which may cause interference with normal delivery.) Luckily during my second (18-22 week) ultrasound I asked the sonographer how long the ultrasound would take. When I was told it would be between 45 minutes to 1 hour I was shocked. I wasn’t ready to expose my baby to potentially harmful sounds and heat. My sonographer was very helpful and explained everything that she does during a routine 18-22 week scan, and I opted not to have all the measurements done to make the scan as quick as possible. Ultimately she showed us the baby moving, took some pictures, and most importantly reported where the placenta was so that my midwife could have this information.
What is checked /measured during the 18-22 week ultrasound:
- Check that baby is developing normally
- Measures length of limbs, heart, head circumference, length of spine to see how well baby is growing
- Sex of the baby
- Check the umbilical cord and amniotic fluid
- Babycentre.ca has a comprehensive list of what the sonographer looks at and what abnormalities can be seen, and what if there are signs of problems http://www.babycenter.ca/a557390/second-trimester-ultrasounds
I wish I had this information before my first ultrasound so I could have specifically asked the sonographer to ensure that she reported where the placenta was so that I could avoid having to do the second trimester ultrasound. Lesson learned- the more questions you ask, the more you know, and the more you can prepare yourself and make decisions for you and your baby rather than assuming that routine scans are safe.
If you are not convinced of the safety of such machines on your baby here is what you can do:
- Ask your midwife/OB to use a fetoscope instead of a Doppler when checking for the heart beat at your monthly/weekly appointments.
- Ask your practitioner as many questions as you need to about any equipment they use on you and baby. Or find out what the equipment is called, what it does and do some research on your own
- Find out how long each of your ultrasounds will take
- Find out exactly what your practitioner is looking for in the ultrasound. Find out what the important information is they need, and what is just the ‘nice to have information’ if you’re looking to limit exposure time.
- To limit baby’s exposure, opt only to look for and measure what’s necessary as required by your practitioner
- Ask your practitioner if there is anything that can be done to remedy the situation if there are abnormalities or concerning outcomes from your ultrasound. (Remember any abnormalities could potentially be a false reading, and there is probably nothing you can do about it, which will just cause you to worry and bring stress to you and the baby for the next few months until baby is born.)
- Ask your sonographer questions, they may tell you something your practitioner hasn’t mentioned.
The absence of human studies showing us hard and fast evidence of the effects of ultrasound scans and electronic fetal heart monitors doesn’t show that there is no effect, but only implies that we need to be vigilant and protect our babies and make the best decision for him or her that we can by outweighing the pros and cons and making the best and informed decision we can as parents. In researching for this post, all of the research has concluded that the risk to human fetuses when using diagnostic ultrasound appears to be minimal if certain rules are followed, such as performing a scan when medically indicated, and using the lowest output power consistent with acquiring the necessary diagnostic information and keeping the exposure time as low as possible for accurate diagnosis. (6)Which leads me to one last question; are these rules being followed?
References & Sources:
- Avoid Fetal “Keepsake” Images, Heartbeat Monitors U.S. Food & Drug Administration. www.fda.gov/downloads/ForConsumers/ConsumerUpdates/UCM095602.pdf
- Barnett, Stanley B. 2000 Intracranial temperature elevation from diagnostic ultrasound. ScienceDirect http://www.sciencedirect.com/science/article/pii/S0301562901003672
- Samuel, Eugenie. 2001. “Fetuses can hear ultrasound examinations.” New Scientist.www.newscientist.com/article/dn1639-fetuses-can-hear-ultrasound-examinations-.html. Accessed 11 May 2006.
- Miller, M.W., et al. 2002. “Hyperthermic teratogenicity, thermal dose and diagnostic ultrasound during pregnancy: implications of new standards on tissue heating.” Int J Hyperthermia 18(5): 361–84.
- “International Programme on Chemical Safety. Environmental Health Criteria 22. Ultrasound.” 1982. United Nations Environment Programme, International Labour Organisation and International Radiation Protection Association. www.inchem.org/documents/ehc/ehc/ehc22.htm.
- Abramowicz JS, Kremkau FW, Merz E 2012. “Obstetrical ultrasound: can the fetus hear the wave and feel the heat?” Pubmed www.ncbi.nlm.nih.gov/pubmed/22700164
Barnett, S.B. “Can diagnostic ultrasound heat tissue and cause biological effects?” In S.B. Barnett and G. Kossoff, eds. 1998. Safety of Diagnostic Ultrasound. Carnforth, UK: Parthenon Publishing.
Nelson, Thomas R & Abramowicz, Jacques S. “Ultrasound Biosafety Considerations for the Practicing Sonographer and Sonologist”