Three soft, flexible, wireless sensors allow movement, provide more precise data.

Laboring mothers have been wearing the same cumbersome, polyester fetal-monitoring belt for decades. Not only can these belts slip out of place, requiring constant adjustment, they -- along with the array of other wires taped to the mother for monitoring -- tether the mother to the bed, limiting her ability to walk around or move freely in ways that are more comfortable.

Now an interdisciplinary team of researchers led by Northwestern University and The University of North Carolina at Chapel Hill is replacing all the belts and wires with three small, thin, soft, flexible, and comfortable wireless sensors.

The new wearable devices measure the mother's and baby's vital signs as well as provide new data, including information about the mother's physical movements and laboring positions, that cannot be collected with current technology. Because the devices seamlessly stream data straight to a physician's smartphone or tablet, the sensors open new possibilities for remote monitoring, which is particularly important during the pandemic and for mothers who live in remote, rural areas.

The research – conducted by materials scientists, obstetricians, dermatologists, anthropologists, and electrical engineers – will publish during the week of May 10 in the Proceedings of the National Academy of Sciences.

The study includes data from more than 500 women, who wore the wireless sensors alongside traditional monitoring systems during labor in both high- and low-resource settings. The team is currently testing the device on a cohort of 15,000 women during various stages of pregnancy, labor, and post-partum. So far, study results indicate that the wireless sensors outperform current technology in precision and accuracy.

"Pregnancy monitoring really hasn't changed for decades. Compared to some of the technology advances we see in cardiology or imaging, women's health has lagged behind," says Northwestern's Dr. Shuai "Steve" Xu, co-senior author of the study. "To be able to generate new innovation and new technologies to make caring for women easier -- as well as more helpful for physicians -- has been an honor for our team."

"We are replicating the function of gold-standard monitoring equipment with affordable, easy-to-use, patient-centric devices," says bioelectronics pioneer John A. Rogers, who led the device development. "We can use these devices in nearly any setting – from an advanced, high-resource hospital to a remote health clinic or home – all with clinical-grade quality and precise data collection. In fact, it turns out that, in certain important ways, our wireless devices actually exceed the capabilities of monitoring systems currently used in top hospitals."

Xu is an assistant professor of dermatology at Northwestern University Feinberg School of Medicine, a Northwestern Medicine dermatologist and medical director of the Querrey Simpson Institute for Bioelectronics (QSIB). Rogers is director of QSIB and is the Louis Simpson and Kimberly Querrey Professor of Materials Science and Engineering, Biomedical Engineering and Neurological Surgery at Northwestern, with appointments in the McCormick School of Engineering and Feinberg. Xu and Rogers co-led the study with Dr. Jeffrey Stringer, professor of obstetrics and gynecology at UNC-Chapel Hill, where he directs the Division of Global Women's Health. 

Continuous, advanced monitoring When a woman is in labor, health care workers connect her to several continuous monitoring systems to ensure mother and baby are healthy and safe. Two separate belts are strapped around the mother's abdomen to measure the baby's heartbeat and the length, strength, and frequency of the mother's contractions. The mother also wears wired electrodes, stuck to her chest, to measure heartbeat and heart activity as well as a clip on her finger to measure oxygen levels.

The Northwestern and UNC-Chapel Hill team's devices replace all of these belts and wires. Embedded with Doppler technology, one single, flexible device softly adheres to the curve of the mother's abdomen to monitor both the baby's heartbeat and the mother's contractions. A second device – the size of a postage stamp – adheres to the mother's chest to monitor her heart and core body temperature. And a third device wraps around her finger to monitor oxygen levels and peripheral body temperature.

"Eliminating the wires not only increases the comfort and freedom of movement for the mother, but it also leads to more reliable data," Rogers says. "The wires and the forces they impose on skin-adherent sensors can be a significant source of electrical noise. We can remove that noise to yield improved data on the health of the mother and baby."

All three wireless devices also communicate with one another to acquire more advanced metrics than currently possible with today's technologies, including continuous blood pressure monitoring, which is particularly crucial for patients with complications such as preeclampsia.

"Measuring continuous blood pressure is a new metric we can capture," Xu says. "We know that blood pressure disorders in pregnancy are a big driver of morbidity and mortality in our country as well as in the developing world. Having the ability to continuously check blood pressure is really important." 

'It's incredibly freeing' Delivering a baby is already a massive physical, emotional and mental challenge. Oftentimes, this challenge comes with tradeoffs between comfort and precise monitoring. Although the mother might want to move around to find comfortable positions, that movement can sometimes displace traditional, wired monitoring systems.

"Being able to move, breathe and feel comfortable during labor is so important," says study co-author Dr. Jessica Walter, an obstetrician and gynecologist at Northwestern Medicine. "Mothers often don't want to move because the monitoring bands can slip out of place, and they don't want the bands to have to be readjusted. It can be uncomfortable when physicians and nurses move and push on those sensors."

Already a mother of a young child, Walter was pregnant with twins throughout the study. When she tried the wearable devices on herself, they were comfortable and completely unnoticeable underneath her T-shirt. She could even add a second abdominal device to differentiate between the twins.

"It's incredibly freeing to have a small sticker on your chest and belly," Walter says. "I completely forgot about them. Yet they collected the same information as a hospital -- all while I was naturally moving around."

Walter and the researchers imagine these sensors could be used throughout a woman's pregnancy to provide remote monitoring between in-person doctor's appointments. The wireless, waterproof devices can be worn in the shower and during exercise.

"We wanted to make these devices so easy and convenient to use that it's not extra work for the mother," Xu says. "Pregnant women go to work, to the gym and have active, busy lifestyles. Current monitoring systems cannot be worn as women go about their day. We want women to be able to wear our technology and forget about it." 

First tech for tracking labor position Because the abdominal device contains an accelerometer, it can track the mother's movements. This data could yield new insights into the importance of specific positions during labor.

"Physicians and nurses ask mothers to make a lot of position adjustments during labor to increase blood flow to the uterus, for example," Walter says. "If we could look back at data to see if baby looks better when mom is on her back or side, then we could actively study those positions to make different recommendations, making labor even safer for mom and baby."

"This is the only technology that we're aware of that can link mother and baby's vital signs to the mother's body position," Xu says. "Positional changes can be consequential. For the first time ever, our system allows us to quantify those benefits, opening up a rich area of future analytics and evidence-based obstetrical care."

Transforming health care in low-resource settings The Northwestern and UNC-Chapel Hill team has deployed the device internationally, starting with hospitals in Zambia, Ghana, India, and Kenya. The affordable, clinical-grade system could potentially be particularly valuable in low-resource settings in the developing world.

"Developing these kinds of technologies, taking them out of an academic laboratory setting and launching them in a context where their value is impactful in terms of saving lives -- that's what we aspire to accomplish with this work," Rogers says. "In these parts of the world, mortality rates can be alarmingly high during childbirth. The ability to track the health of the mother and baby at a precise level, continuously throughout the birthing process, is very valuable.

"Childbirth is a dangerous and traumatic event, even in the best of circumstances where parents have access to the most advanced systems available in health care," he says. "Inadequate equipment and insufficient health care personnel can create significant challenges. Our technologies have powerful potential in these contexts."

Fitted with a small, thin, rechargeable battery, the devices are stable, with reliable power in rural settings. Using Bluetooth technology, the devices wirelessly transmit data to a nurses' station displays or directly to a smartphone or tablet.

"The beauty of the technology is that it can operate with a wide range of mobile devices without sacrificing accuracy," Xu notes. "You don't need expensive equipment that requires a specialized engineer to install."

Rogers and Xu are working with UNC-Chapel Hill's Dr. Stringer to use the technology to identify potential warning signs during labor. Using data from mothers and babies, the team is developing new algorithms that can identify women's risk of adverse outcomes and help predict and plan for interventions. These precision approaches can lead to earlier intervention and better health outcomes for mothers and newborns.

"The low-cost wearable sensors are both advanced technologically and highly usable in low-resource settings," Stringer says. "The sky is the limit for this monitoring technology. I think it will transform maternal-child health outcomes."

This total was an increase of 16.1% from February 2021 and a 41.6% increase over March 2020.

U.S. Manufacturing Technology Orders totaled $437.9 million, an increase of 16.1% over February 2021 and an increase of 41.6% over March 2020, according to the latest U.S. Manufacturing Technology Orders report published by AMT – The Association For Manufacturing Technology. Total orders for 2021 reached $1.1 billion, almost one-third above the total orders in the first quarter of 2020.

“It is noteworthy that total orders in the first quarter were significantly higher than total orders in Q1 2020, given the strength of the first three months of 2020, when the pandemic had not yet affected the industry,” says Douglas K. Woods, president of AMT. “And while these are certainly impressive numbers, they should have been even higher when looking at Oxford Economics’ prediction that U.S. GDP could have been 9.2% had inventories been at their normal levels versus the 6.4% actually achieved for Q1 2021. The good news is they predict that Q2 2021 growth will likely be upwards of 12%.”

“Drilling into sectors, agricultural, construction, and mining machinery orders more than doubled from last month; and recreational equipment, including boats, motorcycles, snow mobiles, and ATVs, were all very strong. Two notable industries which saw declines over February 2021 were automotive and aerospace, two sectors which typically drive manufacturing growth, highlighting just how strong orders from other sectors were in March.”

Trelleborg and other industry experts explain the material-related requirements of the MDR and how to achieve them.

Trelleborg Healthcare & Medical offers device manufacturers that supply products to Europe a free to download webinar about the upcoming Medical Device Regulation (MDR) and how this specification can be met.

The EU MDR takes effect May 26, 2021 and aims to protect patients from risks posed by medical products. For manufacturers in the Americas selling such products globally, compliance with international regulations is complex, with requirements varying significantly depending on the intended use, the type of contact with the patient and its duration.

In the webinar, Tackle MDR requirements with your supplier's material expertise, Trelleborg and other industry experts explain the material-related requirements of the MDR and how to achieve them. Stefan Bolleininger from the consulting firm be-on-Quality, who knows the potential risks from experience, describes test processes that help achieve MDR compliance. He also explains how important a meaningful risk analysis is and how it is conducted.

Two experts from Trelleborg Healthcare & Medical, Verena Hoerner and Andreas Schmiedel, provide detailed insight into the businesses’ MDR strategy and how it supports medical device manufacturers in meeting MDR material requirements. They guide webinar participants along a pathway of relevant standards, such as ISO 10993 for evaluation of biocompatibility, leading to MDR compliance of the final product.

Following extensive investment in R&D, Trelleborg Healthcare & Medical offers materials specifically developed for medical devices and to meet MDR in various applications. Based on extensive test results it can specify the optimum solution.

Verena Hoerner, project development engineer, says: “Because elastomers are subject to a chemical crosslinking process during manufacturing, simply checking the formulation is not always effective. Therefore, we use detailed extraction tests to assess the suitability of materials for use in specific medical applications. This knowledge is often considerably more informative than checking the individual ingredients.

“In addition, in order to comply with the MDR's basic principle of maximum patient safety, Trelleborg Healthcare & Medical has implemented a quality management system in accordance with ISO 13485 and takes a risk-based approach to managing its processes.”

The total was up 3.3% from January’s $144.8 million and down 17.1% when compared with the $180.3 million reported for February 2020.

February 2021 U.S. cutting tool consumption totaled $149.5 million, according to the U.S. Cutting Tool Institute (USCTI) and AMT – The Association for Manufacturing Technology. This total, as reported by companies participating in the Cutting Tool Market Report collaboration, was up 3.3% from January’s $144.8 million and down 17.1% when compared with the $180.3 million reported for February 2020. With a year-to-date total of $294.3 million, 2021 is down 20.2% when compared to February 2020. Please note, AMT and USCTI have revised monthly press release totals back to 2015 to provide the best possible data possible to the community.

These numbers and all data in this report are based on the totals reported by the companies participating in the CTMR program. The totals here represent the majority of the U.S. market for cutting tools.

According to Bret Tayne, president of USCTI, “The recently completed February cutting tool sales statistics continues the trend of slow improvement in our industry. Other sectors of the economy appear to be recovering at a faster pace. Factors such as supply chain challenges, reluctance in a portion of the workforce to return and rising material prices may be causing some drag on the cutting tool industry’s emergence from the COVID downturn.”

Personalized sweat sensor reliably monitors blood glucose without finger pricks.

Many people with diabetes endure multiple, painful finger pricks each day to measure their blood glucose. Now, researchers reporting in ACS Sensors have developed a device that can measure glucose in sweat with the touch of a fingertip, and then a personalized algorithm provides an accurate estimate of blood glucose levels.

According to the American Diabetes Association, more than 34 million children and adults in the U.S. have diabetes. Although self-monitoring of blood glucose is a critical part of diabetes management, the pain and inconvenience caused by finger-stick blood sampling can keep people from testing as often as they should. Scientists have developed ways to measure glucose in sweat, but because levels of the sugar are much lower than in blood, they can vary with a person's sweat rate and skin properties. As a result, the glucose level in sweat usually doesn't accurately reflect the value in blood. To obtain a more reliable estimate of blood sugar from sweat, Joseph Wang and colleagues wanted to devise a system that could collect sweat from a fingertip, measure glucose and then correct for individual variability.

The researchers made a touch-based sweat glucose sensor with a polyvinyl alcohol hydrogel on top of an electrochemical sensor, which was screen-printed onto a flexible plastic strip. When a volunteer placed their fingertip on the sensor surface for 1 minute, the hydrogel absorbed tiny amounts of sweat. Inside the sensor, glucose in the sweat underwent an enzymatic reaction that resulted in a small electrical current that was detected by a hand-held device. The researchers also measured the volunteers' blood sugar with a standard finger-prick test, and they developed a personalized algorithm that could translate each person's sweat glucose to their blood glucose levels. In tests, the algorithm was more than 95% accurate in predicting blood glucose levels before and after meals. To calibrate the device, a person with diabetes would need a finger prick only once or twice per month. But before the sweat diagnostic can be used to manage diabetes, a large-scale study must be conducted, the researchers say.

The authors acknowledge funding from the University of California San Diego Center for Wearable Sensors and the National Research Foundation of Korea.

The abstract that accompanies this paper is available here.