A new sensor to measure and monitor fetal movements in the womb



thank you very much for the invitation to speak here today in front of you for being here and so today I'm going to talk about and feed the movement so just just a background so I'm actually an engineer bioengineer in the Department of bioengineering and collaborating closely with clinicians and particular doctor Christophe Lee's who's here today fetal movement so what do they look like so here we see cine MRI data and from fetuses ranging from 18 to 38 weeks so this is data from collaborators at King's College London at formerly of Imperial College actually and you can see that from very early on babies fetuses move a lot and they're very very highly active a whole range of different activities that they do so they turn around they move their limbs they move their heads their jaws their lungs every everything's moving and by the time the baby gets to this thirty a week so that's that's term basically you can see that there's very little space to move and in particular for this baby this is a baby's in a breech position and so has even less freedom to move around so and fetal movements so for a lot of this talk I'm going to talk about how fetal movements are important for skeletal development so devout them to the bones and joints but fetal movements are a really important indicator of the health of the baby so about a quarter of women that sense decreased fetal movements themselves have poor outcomes at birth such as preterm birth or small-for-gestational-age and there are there is data to suggest that a high proportion of still births are preceded by a period of decreased fetal movements and the problem with fetal movements as an indicator of health is that it's actually quite subjective and it depends a lot on it will vary from woman to woman and what she may feel or be aware of and so there is the only way at the moment to reliably monitor fetal movements is is with an ultrasound or with other technologies in in a hospital setting so um in so together with a collaborator in mechanical engineering and with mr. Lee's here in Queen Cheryl we've been working on developing new type of sensor for fetal movements and so it is it is quite an early stage study at the moment and but what we've been doing is using acoustic sensors so so people have tried using accelerometers to measure fever movements so that would basically be it measures movement at the bump have a handy demonstration here for you but the problem with accelerometers is any time the woman moves obviously the accelerometer will pick up activity and so the our idea is to combine accelerometers to measure movement of the mother with these type of acoustic sensors so they're actually originally developed for measuring muscle activity so what they do is they're very very sensitive to vibrations and so we and so what we did was we have so this these are the acoustic sensors here that's what they look like and this is the the idea of the wearable version where each of these white circles is one of these individual acoustic sensors so what we have done so far is that we last no sorry – some two years ago because this was me actually when I was pregnant last time very handy being pregnant when you work in fetal movements we did a small study of so 44 women where we did we validated the sensor where we had sort of just the sensors on the accelerometer so not the wearable based off the material but and did concurrent ultrasound scanning and so and what we found is that the sensor is good at picking up startled movements so here the startle movements are the red red circles and we see a pretty good correlation where we're able to pick up about three-quarters of the startle movements that the baby does and not so good on breathing movements which in a way we expected because the breathing movements are very quite subtle and the mother wouldn't be able to feel that either and and also generally moving so and so just to define what startle movements are or what we define them as they're the very quick forceful movements that the baby does and actually what's interesting is that not only can we detect most of the styrofoam movements we can also discriminate between them so we can tell with reasonably good accuracy how whether a start that a start a movement is different to the other sense the other signals that we're picking up so the it's still definitely in development so we have a paper under review at the moment and what we need to do we need to technology further because at the moment it's not accurate enough to be able to say this baby is moving enough or this baby is not moving enough word word we're not at that yet but we hope to get to that and within a few years um so um oops so and now so I'm gonna talk about bones now and actually I brought a prop with me that I'll pass around so and these are this is 3d printed fetal bones at 20 and 30 gestational weeks so these are the what's what's passed around and what's you see the picture of they're the real sizes and you know pretty much the real shapes so basically they change and obviously babies grow so they change in size but also their shapes of the bones and joints change as a baby develops and what my group is working on is how fetal movements contribute to that process of skeletal development and so fetal movements are really important for normal development of the of the skeleton there are a number of conditions in which abnormal fetal movements will lead to or reduced or restricted fetal movements will increase the chances of skeletal abnormalities what the most common of these is developmental dysplasia of the hip which is where the hip joint is unstable when the baby's born or soon afterwards another is arthrogryposis it's a rare it's about one and three to five thousand births but that's where there's multiple joint shape abnormalities or multiple joint contractures and congenital scoliosis the very limited research on this but there it in I think 50 percent of babies with arthur cry poses they also have congenital scoliosis so there seems to be a link there with fetal movements at the very severe end of the scale is fetal akinesia deformation sequence our fads that's when the baby doesn't move at all it's very rare thankfully to you it's almost always near your natal lethal because the babies can't breathe and then another sort of this is not prenatal or fetal this is postnatal and metabolic bone disease of prematurity occurs in extremely preterm babies and it is thought that so part of it is nutritional there so these babies who miss out in the last trimester and they're missing out on a lot of nutrition or there's all nutritional differences but also mechanical differences so an or a baby that is goes to term and has a very different mechanical environment to a baby that's born extremely preterm preterm and maybe have other health concerns and so um these skeletal conditions aren't just a problem for babies they're also problem into life so for example hip dysplasia is responsible about ten percent of all adult hip replacements an art degree poses is linked with early onset osteoarthritis and preterm birth linked to osteoporosis so the in the group in general our aims are to understand the biology and the mechanobiology of normal skeletal development and of conditions such as the ones I've just described and to address unmet clinical needs in the diagnosis prevention and treatment of musculoskeletal conditions that are impacted by the pre or post natal mechanical environment so I'm just today what I'm going to talk about is the what what's happening in normal baby as it moves you know what what what what effects does the movement of the baby have on the bones and joints and what is the link between reduced movements and developmental skeletal conditions and in particular hip dysplasia and so the hip dysplasia just very briefly in a normal hip we have a nice spherical femoral head and a curved acetabulum and it's nicely contained within and with hip dysplasia we have an abnormally shaped femoral head and an abnormally shaped acetabulum in this case completely dislocated this would be not this would be a child and interest so genetics is a factor in hip dysplasia so for example a family history or female gender will predispose or increase the risk of hip dysplasia but all of the other major risk factors are related to movement or mechanical environments so low amniotic fluid elekid romeo's and breech position also firstborn babies I have a higher risk of hip dysplasia and that's thought to be because there's less flexibility to move for a firstborn child and an interesting exception is twins so twins have roughly half the space but they don't have a higher instance of hip dysplasia so that's an interesting difference there and so the questions we're asking is what my mechanic biomechanical stimuli so I'm talking about stresses and strains from a mechanical point of view occurred during prenatal development and are these stimuli stress and strain linked to the risk of hip dysplasia so this is the so this work has been done by dr. stephan Verbruggen Huson who's in the room and it was funded by Arthritis Research UK and this is just a over the overall methods so basically the cine MRI data they showed earlier on we track the movements of the baby from that we do what's called a musculoskeletal model which is a computational modeling technique used in gait analysis usually and to predict what muscles are acting and we can measure how much the baby deforms the uterine wall from that directly from the cine MRI data and we can predict from that what the reaction forces when the baby is kicking and I'm actually sorry that feeds into the muscle is lethal model and from that we got our muscle forces and we can apply the muscle forces in another type of computer model called finite element analysis or finite element model to get a picture of actually what are the stresses in the developing bones and joints in individual and babies so for the finite element model we needed to have geometry so in with a collaborator in Great Ormond Street Hospital on UCL i CH we were able to guess am i right normal MRI scans of babies and that's where the 3d printed bones that are going around came from and so we first of all looked at what happens in over normal development so we looked us 20 25 30 and 35 gestational weeks each of these we looked at five different kicks and two different geometries so first of all just the measurement of how much the baby deforms the uterine wall so this is directly from the cine MRI scan and it's similar to by 12 millimeters so baby baby's between 20 and 30 weeks are deforming when they do a really strong kick they're deforming the wall by about 12 millimeters this drops right down at 35 weeks at about four millimeters so we're just really just the baby just is so restricted interestingly though when we calculate what the reaction force is due to those movements we see an increase between twenty and thirty weeks but then still a drop or 35 weeks and when we look at the stresses induced in the bones over time we basically see an increase with gestational age so here we're looking at two different ages twenty and thirty weeks and this is the stresses and if we look at the different joints we can see that there's definitely an increase between twenty and thirty weeks with a similar sort of distribution of the patterns and if we look quantitatively and we see pretty much increases over the whole Soph between twenty to thirty five weeks and and the interesting thing here is that this is the increase at 35 weeks since despite the decrease in both displacement of the uterine wall and the reaction force at that later stage and so we see an age dependent increase in stresses and strains in the developing skeleton over the second half of gestation and this implies that even those late movements the movements when the baby doesn't have very much sorry the time when the baby doesn't a very much room to move are important for the skeleton and then finally then just to talk a little bit about hip dysplasia so here this is a normal cephalic fetus here um this is a breech baby so around the same age so you can see the babies trying to kind of extend a leg the way the first one is but kind of quite make us doesn't have enough room and a leg hide Romney also so in the first two videos the kind of light gray or white is amniotic fluid in the third one that's basically almost no I'm not a fluid there and the baby doesn't move very much at all and then finally twins so we marveled all of these scenarios so we applied the same methods that I showed you before to these different scenarios we looked at five different kicks for breech and for twins three kicks for illegal nails the problem we have way more scans than that but the problem was was very hard to actually find babies that were doing something could be enough of a kick that could be modeled and all of these were most of these were twenty weeks but the day legged Romney us were a little bit older and we also looked at firstborn vs. and non firstborn babies and and what we found oops what we found was that for breech and elyda Hydra meows so both of which are risk factors for hip dysplasia we saw a significant decrease in stress and strain stimulation of the hip joint wears for twins who have the same risk of hip dysplasia Singleton's we see that we see no significant difference between in the stimulation of the hip joint and when we looked at first Born's versus non first Born's we saw a decrease in the amount of displacement that the baby can apply but it was only it was it was it was small and actually when we looked at the stimulus that the hip joint it wasn't significant difference but there was a trend there that firstborns have lower stress stimulation of their hip joints and so just to conclude so biomechanical stimulation of the fetal skeleton increases over gestation and this increasing trend has despite the smaller movements of the baby can make in later station and that we see significantly decrease in the Camco stimulation of the hip in breech and a legged romeo's but not in twins which suggests a link between mechanical stimulation and hip dysplasia risk and just in terms of how how will this research help or how we hope it will help we hope that understanding how and when movements are most Horton's will help with eventually help with early diagnosis of conditions like hip dysplasia and artha crows – so for example arthrogryposis very few babies I think less than 50% babies are diagnosed before they're born and raised awareness the clinical importance for people move on food and other movements for school development and perhaps there may be a way to increase movement in cases where there's the risk of hip dysplasia so for example breech babies are currently turned at 37 weeks with the sole aim of having a cephalic position before birth and they used to be turned at 34 weeks and we suggest that if babies were turned earlier that that might help with hip health so just to acknowledge funding sources the group and in particular Stefan who's there in the middle who did all this great mopping work and thank you very much for your attention [Applause]

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