Tuesday, 7 December 2010

What effect does ultrasound have on growth restricted babies?

Some years ago, a research project from WA suggested that babies who were repeatedly subjected to ultrasound to check their growth, were in fact even smaller because of that ultrasound intervention. That idea was dismissed later because the babies did not seem to have any long term effect.

A midwifery colleague asked on an email midwifery list if anyone knew of any follow up studies to that work done in Perth, WA. 

This question piqued my interest, so I had a look at the effect of ultrasound on cells. Ultrasound is used therapeutically for various physical problems e.g. rehab and to detect fetal anomalies.

I've fallen in love with cells lately and am finding them eminently fascinating. 
This human physiology site has some wonderful graphics about cells, such as the one below,  including simulated videos of cell structure, function and behaviour. Well worth exploring! 

I found some links with information worth investigating:
This article explains how ultrasound can blow holes in cell membranes
and the following abstract has a bit more on holes and bubbles
This article is aimed at horticultural interests. How amazing it is what ultrasound can do at different intensities
and I quote from the above article:
"It showed that ultrasound is capable to peptize soy protein at almost any commercial throughput and that the sonication energy required was the lowest, when thicker slurries were used. (Moulton et al. 1982)"
Not that we can call the substance in human cells 'slurry' but I wonder if the density of that substance affects the way that ultrasound works in pregnancy?
and just what is ultrasound doing to bones?
Cancer cells get blasted with high intensity ultrasound, however, I wonder what ultrasound does to fetal mitochondria?

low pressure and high pressure effects on cells noted in this abstract from Japanese investigators
and from Czech Republic, microtubules and microfilaments (essential cell components) are the subject of examination when ultrasound is coupled with cytostatic drugs in this study reported below:

and then E Coli were not that fussed on ultrasound:
That article is particularly good and easy to read. I was a bit uncomfortable when I read that the researchers noted: "cell viability decreased exponentially with time at different intensities of ultrasound"

However, there are some amazing therapeutic applications for ultrasound as explained in this video by Yoav Medan, who with his team is "developing a tool for incision-less surgery via focused ultrasound". In this video, the techniques are explained and in the comments, you will see that someone has asked about the safety of ultrasound in pregnancy. The reply is that ultrasound is safe in pregnancy as the frequncy used scan a fetus is lower than that used elsewhere.
These following studies are particularly interesting when we consider fetal growth restriction from ultrasound, as this one focuses on what happens to fat cells with rats
and this one with men
That last couple are fascinating aren't they?  Do you think that gives us a bit of a window into what may be going on with the observations around ultrasound adding to growth restricted babies' physical development?

The question is, what can we do differently?  I have some ideas on that. Look for another blog post on this subject.

Just to add another lens on this fat shrinking/blasting idea, here's how the ultrasound machine makers are reaping the benefits of this versatile technology in another realm of people's fears - the 'perfect body syndrome' also disguised as the 'obesity epidemic' with 'fat' as the enemy.


Anonymous said...

Very interesting... and worrying! A woman I'm midwife for recently had an ultrasound. She asked the ultrasonographer if there were any risks to u/s. The ultrasonographer said 'I hope not because my daughter has one every week'.
If the practitioners using the machines don't know the risks, how can they inform women?

Carolyn Hastie said...

A worrying trend altogether! Many women are having multiple ultrasounds. Women are telling me that doctors use ultrasound at every antenatal visit 'to check the baby'. So it seems that the art of palpation is being given up by doctors, they prefer technology. Perhaps they subconsciously recoil from touching women's bodies in such an intimate way? Not sure about that - they don't have the same issue with vaginal examinations. Whatever the reason that ultrasound is being increasingly used in pregnancy, I feel concerned. Not only am I concerned about the effect of the ultrasound on the developing cells, but also on the ability of the practitioner to properly assess a baby's wellbeing. I have found that when I palpate a woman's abdomen and feeling the amount of liquor, the movements of the baby, getting a sense of the baby's position and response to touch builds a picture of the baby's health and robustness.

Chrissy said...

I can't believe I've only just found this post. I now have much evidence to share when people ask the question as to why I don't support the routine use of ultrasounds in pregnancy, all in the one place. Thank you Carolyn.

Carolyn Hastie said...

Glad you find the post useful Chrissie! I can see the value of an ultrasound when there is a clinical issue, but I do feel concerned about multiple and 3D ultrasounds for no clinically indicated reason.

Anonymous said...

Ultrasound can be used to blast sperm and create a temporary sterility as birth control for men, so it's comes as no surprise that it can have negative effects upon the fetus.

It is technically simple and extremely convenient in that fifteen minutes of ultrasound can result in six months of sterility.