A Contraction Monitor for Mothers-to-Be in Low-Resource Settings

A Contraction Monitor for Mothers-to-Be in Low-Resource Settings

A team of bioengineering students designed, built, and programmed a sensor and test rig to monitor women in labor.

By Mike Williams, Rice University04.02.18

Rice University seniors are developing an efficient and inexpensive uterine contraction monitor to help save the lives of mothers in labor and their newborns in resource-poor settings.
A team of bioengineering students who call themselves Contractionally Obligated designed, built and programmed not only a sensor to monitor women in labor but also a unique test rig. They plan to validate the monitor’s accuracy with the help of faculty at the University of Texas Health Science Center at Houston (UTHealth) and their patients.
Eventually, the monitor will likely be tested in maternity wards at hospitals in Malawi, where the Rice 360˚ Institute for Global Health is working to solve the challenges they and other low-resource hospitals face.
“Maternal mortality is a large problem in Malawi,” said Leah Sherman, one of two team members who has spent time there with Rice 360˚. “We’ve seen the wards, which isn’t something you can easily forget, and we all have a passion for bringing the maternal mortality rate down. Of all of the bioengineering projects we were offered, this one seemed the most powerful and impactful for a community that is in dire need.”
Sherman and Mildred Antwi-Nsiah, who has also worked in Malawi, were joined in the effort by teammates Aniket Tolpadi, Patricia DaSilva, Shannon Fei and Catherine Schult. All spent long days this school year at Rice’s Oshman Engineering Design Kitchen (OEDK), where some designed and programmed the sensor and monitoring algorithm and others pieced together a method to test their invention.
“In Malawi, nurses are supposed to perform a partograph, in which they manually measure contractions every 30 minutes for 10 minutes, but the patient-to-nurse ratio is 15-to-1, so it’s not physically possible to adequately monitor all the patients,” Sherman said. “Most mothers there go unmonitored for the majority of their labor.”
The heart of the Rice device is a puck-like sensor that presses against the patient’s abdomen and is held in place by a robust, washable rubber and nylon belt designed by the team to lessen the need for disposable supplies and cut the risk of infection. Contracting muscles move a membrane on the sensor, which in turn moves an LED on the inside closer to a photoresistor that measures the intensity of the light and determines the voltage output to a microcontroller. That sends information about the contractions to the user interface in real time.
When contractions become more frequent or indicate a risk to the patient, a box attached to the computer will light up and sound an alarm, Antwi-Nsiah said. “When they’re outside of a safe physiological range for more than 10 minutes, the audible and visual cues will become more intense,” she said.
Because contractions can last between 30 seconds and three minutes, the team’s test device had to deliver a gradual increase and decrease in pressure to the sensor. A beach ball hooked to a set of microcontroller-controlled solenoids was the answer. “We started with a hand pump, but it was hard to get the nice, smooth curves you would get in real life,” Schult said.
The contraction monitor is designed to cost less than $100, according to the team.
The students plan to test the monitor at UTHealth under the supervision of Dr. Suneet Chauhan, a professor in the Department of Obstetrics, Gynecology and Reproductive Sciences. Chauhan is co-advising the team with OEDK Director Maria Oden, a teaching professor in bioengineering; Eric Richardson, a lecturer in bioengineering, and Jennifer Carns, a postdoctoral researcher in the lab of Rice 360˚ Director Rebecca Richards-Kortum.
Validation will be done in parallel with devices used by UTHealth faculty in their practices, though the Rice team won’t hook up its graphical interface so attending physicians will only have access to their own monitors, Schult said. “Also, for some women who have higher-risk pregnancies, they often monitor them with an intrauterine pressure catheter (IUPC), which is the gold standard and very accurate.
“If our device detects 70 percent of contractions relative to those detected by that (IUPC) technology, it will be equivalent to the tocodynamometer used in the United States, which is our base goal.”
Contractionally Obligated will demonstrate its device at the annual George R. Brown School of Engineering Design Showcase April 12 at Rice’s Tudor Fieldhouse. The event opens to the public at 4:30 p.m., with the winners of cash prizes announced at 7. More than 80 teams are expected to compete this year.
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