Drexel’s engineers, designers and clinicians have created the smart fabric Bellyband – a fabric-based, wireless biometric system for monitoring uterine contractions and fetal heartbeat during pregnancy. Bellyband is designed to replace currently used bulky fetal and contractions monitors that connect to stationary monitoring equipment with cables, which is inconvenient for the expectant mother and restricts her mobility. Disconnecting the cables to allow mobility interrupts monitoring, which is very undesirable, especially in cases of high risk pregnancy. Smart fabric Bellyband will increase patient mobility and decrease cost for hospitals while providing the same level of information.
The Bellyband technology can be used in multiple similar applications such as Sudden Infant Death Syndrome (SIDS) monitor and athletic attire for functional performance monitoring, among others.
Clinical Relevancy and Market Need:
A fetal monitor that measures a baby's heartbeat in response to contractions of the uterus will be an important tool to assess fetal wellbeing. Many types of monitors exist that serve the same function. The hospital external fetal monitor standard is a two-belt ultrasound device that is strapped around a mother's belly and attached to a large box next to the labor bed, essentially immobilizing the pregnant woman (Fig. 1). Telemetry monitoring uses radio signals to transmit the baby’s heartbeat, and is the newest type of monitoring available. Telemetry modeling allows expecting mothers to be monitored 24/7 while maintaining mobility. Studies report that the use of small wearable monitoring devices for fetal monitoring is rapidly growing and medical publications support its use.
One study reported that “Continuous annotated ECG (aECG) monitoring of ambulatory women undergoing induction of labor at home is feasible and acceptable to women. The quality of remote signal was of sufficient quality to allow clinical decision making in real time.” Another concluded that “non invasive trans-abdominal fetal ECG (ta-fECG) (Monica AN24) monitoring in labour is feasible and represents more comfortable solution for the patient”. Other studies point out that wearable labor and delivery monitoring devices could become valuable diagnostic tools. “The ability to record the beat-to-beat fetal e.c.g. transabdominally with the very small Monica AN24 monitor has allowed us to record for up to 16 hours overnight, with minimal maternal inconvenience. This will facilitate the identification of subtle changes in fetal heart rate variability and could reduce or abolish the need for alternate day use of antenatal cardiotocography in women with obstetric cholestasis”.
Market Potential:
Monitoring of term laboring woman represents a market opportunity of 4 million patients a year in the US alone. Current fetal monitoring devices sell from $800 to $6000. Small wearable monitoring devices for labor, delivery and fetal monitoring will become
the new standard given that to remain ambulatory is ideal for both the physician and the pregnant women while being desirable for the progression of early labor. In February 2011 the US Food and Drug Administration (FDA) granted 510(k) clearance for UK-based Monica Healthcare’s AN24 wireless fetal monitor for use during labor and delivery. (Fig. 2) The clearance allows AN24 to be used for intrapartum term monitoring for all singleton births in the US, according to the company.
As the adoption of portable monitoring devices increases, they could become a useful tool to help prevent and diagnose problems with the fetus while offering the expecting mother comfort and ease of movement. New data collected through ease of monitoring with mobile devices could help prevent prematurity and stillbirth or early infant death worldwide, which amount to 13 million and 1 million cases, respectively.
In spite of providing mobility, devices like the Monica AN24 are still quite cumbersome with many wires attached to it. Bellyband is a next generation mobile monitor offering increased comfort and convenience of use.
Bellyband:
Smart fabric Bellyband is a garment similar to a tube top, with sensors and communication circuitry built in or knitted in during fabrication. The sensing technology is based on the mechanical stretching and compression of knit fabric passive antennas that convey vital information in the monitoring of the mother and unborn child (Fig. 3). In a mode of operation similar to passive radio frequency identification (RFID) systems, information regarding the mechanically-obtained respiration information can be interpolated by the backscatter power or frequency. Alternatively, passive components can be combined with active circuit elements to improve Bellyband’s performance. Recent experiments on a contractions simulator have demonstrated that Bellyband’s performance exceeds that of tocodynomometer, the current gold standard for contractions monitoring.
The Shima Seiki Haute Technology Laboratory at Drexel University provides a key facility managed by the investigators of this project (Fig. 4). It enables customization and innovation in the design and production of smart textiles. The knitting equipment at Drexel includes sixteen SDS-ONE APEX3 workstations and four state-of-the-art knitting machines. The workstations accurately simulate fabric construction and provide researchers and designers the opportunity to create and simulate textile prototypes, import CAD specifications of final products, and produce made-to-measure or mass-produced pieces on Shima Seiki knitting machines. Among the machines available in this facility, the model SIR122 machine is for inlaying specialty yarns that are difficult to knit, while the model SWG041 machine produces a range of accessory items and small parts, the MACH173 produces a variety of multi gauge shapes and whole garments (i.e., garments without seams) the SSV can knit a variety of circuits. This type of fabric production offers tremendous advantages concerning production flexibility and cost savings. In addition, it significantly reduces material waste, enabling new design approaches and innovation in garment and product development.
As a facility devoted to fashionable technology research, this laboratory is unique in the world, and enables a highly repeatable and customizable approach to smart textile fabrication which is able to take advantage of the most advanced techniques available in the textile industry.