You might be forgiven for thinking I’m inherently anti-technology. That’s not the case at all. I’m currently sitting in front of my desk top computer and it’s secondary screen working on blog post writing. My internet connection comes courtesy of a satellite dish mounted to my roof, and I can monitor my upload and download speeds with a very neat app, residing on my mobile phone. I have already accessed my phone this morning to look at the app that monitors the output from my solar system and another for today’s weather forecast. 1980s Kirsten (proud owner of a Donkey Kong game) would be beside herself with excitement at the cool tech I now have at my disposal.
My concerns about the use of technology in birth do not stem from inherent anxiety about technology. Rather, they are based on concerns that we are too quick to believe that simply because we can build something we imagined then the thing we built must be a good thing! CTG monitoring sprung from someone’s imagination, into existence, and then into practice in the late 1960s. And we are still using it, in spite of a pile of evidence it turned out to not be a good thing after all.
So what’s new and exciting?
Every so often some new technology pops up in the recently published literature about fetal heart rate monitoring in labour that makes me go – oh that is so cooooool!
The new and very cool thing is also a very tiny thing. A French team (Nguyen, et al., 2022) recently wrote about a sensor they are developing for intrapartum fetal monitoring. Not only can it monitor the heart rate in real time, it can also monitor pH and oxygen saturation. The sensor part of the device that would sit on the fetal skin is a very wee 600 micrometers in size. How small is that? Well if you put 16 of these in a row it would occupy less than a centimetre of space.
Unlike fetal spiral electrodes or fetal blood sampling, it doesn’t make a hole in the skin to get the information it needs. That’s a good thing. While not described in the paper, the new sensor continues to have some of the same disadvantages of current technology that we attach to the fetus. It will require access to the amniotic cavity, so the membranes will need to have released either spontaneously or surgically. It will need a vaginal examination to put it into place, and presumably there will be a physical connection to either a monitor, or to a transmitter that pushes the data wirelessly to a monitor. I suspect that its small size will ultimately be a problem and it will be mounted to something larger to make it easier to handle and not be damaged.
What really excites me is the potential for continuous monitoring of parameters that actually reflect fetal oxygenation. At present we rely on fetal heart rate patterns to help us guess whether the fetus is sufficiently well oxygenated or not. But the link between oxygenation and / or pH and heart rate patterns is not all that strong and that’s at least part of the reason we can’t get CTG monitoring to work. By monitoring what we actually want to measure, we might have a clinical tool that can reliably detect falling oxygen levels before harm is done, so clinically appropriate interventions can be used when needed. And be avoided when they aren’t.
It is still a long journey from this wee tiny prototype to a clinical tool, and an even longer one to assess it properly (please, please, please can we get it right this time?). But it gives me hope that we might yet accept that heart rate monitoring isn’t helping and find something better than can.
Reference
Nguyen, T., Besiege, A., Rousset, Q., Journet, B., L’Horset, S., Takhedmit, H., & Lissorgues, G. (2022). pH and SpO2 miniaturized sensors for fetal health monitoring. Proceedings of the 15th International Joint Conference on Biomedical Engineering Systems & Technologies, volume f, 155 – 161. DOI: 10.5220/0010867200003123
- CTG monitoring is NOT mandatory: A request to writers
- Routine umbilical cord gas analysis – is it worth it?
Categories: CTG, EFM, New research
Tags: technology, pH, oximetry
Birth Small Talk 
Interesting! And yes, let us hope it will be assessed before taken into clinical use
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Cool indeed- I can’t wait to hear more about this TINY sensor. Meanwhile I must admit I am impressed by the incredible technology you use at home and all of it being controlled by an app on your phone. How cool is that my friend?
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Does the oxygenation of a blood in a small area of the scalp which is under considerable pressure as labour progresses really reflect the oxygenation of the entire fetus? Long ago I remember a spate of articles criticising fetal blood sampling is the regard.
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It’s a great question Mavis, and one of the many assumptions we take for granted in the fetal monitoring story. We know very little about fetal oxygenation physiology. The original fetal oximetry monitors used the fetal cheek and therefore circumnavigated the issue.
I’d have to look at the literature again, but my memory of it is the relationship between scalp pH and cord pH is fairly strong. But the relationship between cord pH and neonatal outcomes isn’t all that great.
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