Annie Tian | Contributing Illustrator

Fourteen million women around the world, annually, experience postpartum hemorrhage (PPH). 70,000 of those women die as a result of it.  

Primary PPH occurs within the first 24 hours of giving birth and is characterized by excessive bleeding — the loss of over 500 milliliters of blood. It transpires in 3-5% of deliveries. Christine O’Brien, Assistant Professor of Biomedical Engineering, is working to prevent PPH-related deaths — the leading cause of global maternal mortality — by developing wearable technology that detects and monitors the blood flow changes of postpartum mothers, in real time. Despite it being the leading cause of maternal death, PPH is also the most preventable cause of maternal death. If it can be caught before too much blood is lost, it is not fatal.

In addition to teaching “Introduction to Biomedical Circuit,” O’Brien runs the O’Brien Lab, which is focused on helping both low- and high-resource institutions reduce PPH-related mortality by studying light interactions with bodily tissue. 

In the United States, PPH tends to be caught early and treated properly, so it was not until O’Brien took a global health certification course in graduate school that she learned about maternal health issues, such as the severity of PPH, on a global scale.

“Right now, the main way people detect hemorrhage across the globe is by eyeballing a pool of blood and trying to put a number on how much is lost,” O’Brien said.

As hemorrhaging can also happen internally (the uterus can hold a lot of blood), it is common for unskilled postdoctoral residents to not know that a mother is hemorrhaging. The majority of deaths due to PPH happen in low-resource communities, because if hemorrhaging is not detected early enough, these communities often don’t have access to the necessary treatments — like blood transfusion and specialized surgeries — to save a patient’s life. 

The O’Brien Lab is currently working on two low-cost, non-invasive wearable devices that will be able to detect early signs of hemorrhaging and inform physicians about it. The optical-wearable is a large device worn on the wrist that monitors changes in blood flow. The short-wave infrared (SWIR) photoplethysmography sensor identifies blood concentration changes and can be worn anywhere on the body. Dr. O’Brien is working on decreasing the size of the wearables to the size of an Apple Watch. 

“Right now, [patients] can definitely tell when [they’re] wearing [the devices], and it’s a little bit cumbersome,” O’Brien said. “We want to get to the point where people forget that they are wearing them … and [it] doesn’t interfere with their ability to nurse their baby right after delivery.” 

The highest risk of PPH occurs during primary postpartum hemorrhaging, which is often caused by irregular uterine contractions that can lead to sudden high concentrations of blood loss. Secondary postpartum hemorrhaging is characterized by bleeding that is commonly caused by uterine infections between 24 hours and 12 weeks after delivery. 

Right now, the wearables are worn during labor or right before a cesarean section until about four afters after delivery. 

“Our battery doesn’t last 24 hours, so we are currently engineering a project to increase the lifespan of our device … so we can catch as many hemorrhages as possible,” O’Brien said.

O’Brien hopes to expand the capabilities of PPH-detecting technology to commercialize products tied to her lab’s research, in order to reduce PPH mortality rates. 

“The goal is to identify hemorrhage in that window where those low-cost accessible treatments can be successfully administered,” O’Brien said.  

By creating products that support her lab’s research, O’Brien hopes that hemorrhaging mothers will be able to obtain low-cost, accessible treatments — like uterine massages and medications that enable uterine contraction and prevent bleeding — sooner. 

O’Brien’s start-up company, Armor Medical Inc., will eventually manufacture her lab’s technology. In 2023, Armor Medical Inc. received $320,000 from the National Institutes of Health’s (NIH) “Rapid Acceleration of Diagnostics Technology (RADx Tech) for Maternal Health Challenge.” This grant will help the company nationally commercialize an Apple Watch-like device that will monitor blood flow during delivery as well as four hours after. The goal is to release marketable products in the next two-to-three years.  

The O’Brien Lab is also beginning to explore the implementation of their research on a global scale by collaborating with Nigeria’s University of Abuja Teaching Hospital to learn how their research can be adjusted to better help the University’s healthcare team. 

For those inquiring about any type of career in science, O’Brien advocates for students to gain a plethora of different experiences that will help narrow down their interests. If O’Brien had not steered off course to take a global health certificate course, her career and research would have looked very different. 

“Let’s say you have an experience that was maybe not the best — you’re still going to learn something from it and pivot your trajectory,” O’Brien said. “Remember that almost nobody’s career is a straight line.” 

WashU undergraduates studying biomedical engineering have the opportunity to study  historically under-researched women’s health problems through WashU’s Center for Women’s Health Engineering. 

“If [a problem] is important to you, use your skills as an engineer to go and … figure something out or solve it,” O’Brien said.