3D imaging technology captures labor contractions in real time

New imaging technology can produce 3D maps showing the magnitude and distribution of uterine contractions in real time and across the surface of the uterus during labor.

Building on imaging methods long used on the heart, the technology can image uterine contractions noninvasively and in much greater detail than currently available tools, which only indicate the presence or absence of a contraction.

The clinical study, which included 10 participants in labor until delivery, appears in Nature Communication.

“There are all sorts of obstetric and gynecological conditions that are associated with uterine contractionsbut we don’t have very precise ways to measure them,” says lead author Yong Wang, associate professor of obstetrics and gynecology, electrical and systems engineering, radiology, and biomedical engineering at the Washington University in St. Louis.

“With this new imaging technology, we are fundamentally improving the standard method of measuring labor contractions, called tocodynamometry, from one-dimensional tracing to four-dimensional mapping. This kind of information could help improve care for patients with pregnancies at risk and identify ways to prevent preterm birth, which occurs in about 10% of pregnancies worldwide.

During labor and delivery, the uterus contracts to provide the force that pushes the fetus out. The new approach to measuring these contractions, called electromyometric imaging (EMMI), could for example help identify the types of early contractions that lead to premature birth and help researchers identify ways to slow or stop these premature contractions.

Abnormalities in contractions can also lead to a stoppage of labor, which may require a caesarean (caesarean) delivery. Premature births and C-sections can increase the risk of birth injury or death for both parent and infant. Such injuries can include long-term neurodevelopmental disability for the child.

The researchers found that uterine contractions are less predictable and consistent than heart contractions which are typically measured with similar technology. Even with the same patient, consecutive labor contractions may differ in trigger region and direction of progression.

Additionally, the researchers found that there are no consistent areas of the uterus in which contractions begin, indicating that the sites of initiation, or pacemaker, of uterine contractions are not anatomically fixed. , as in the heart. These considerations add more value to the team’s imaging technology, as it can track changes through progressive contractions.

The study included patients who were giving birth for the first time and some who had already given birth. The researchers found that patients who had not given birth before had longer contractions with more variation compared to patients who had already given birth.

This is indicative of a possible memory effect of the uterus. In those who have already given birth, the uterus seems to remember its past labor experience and has more efficient and productive contractions.

Potential clinical uses of EMMI proposed by Wang include:

• Distinguishing productive from non-productive contractions to predict preterm birth in patients with premature contractions.
• Monitor labor contractions in real time to optimize pharmaceutical treatment and prevent labor complications such as lost labor.
• Monitoring uterine contractions to prevent postpartum hemorrhages.
• Develop possible non-pharmaceutical treatments such as mild electrical interventions to normalize contraction patterns.
• Investigate uterus-related conditions outside of pregnancy, such as painful menstruation and endometriosis.

The next step in Wang’s research is to measure normal uterine contractions which would help decipher whether a contraction is productive and leads to birth. Last year, his team received a grant from the National Institutes of Health (NIH) to create a sort of atlas that characterizes what contractions look like during normal labor.

“The goal of this grant is to imagine healthy term labor in 300 patients so that we know what the normal range looks like – for first births and second or third births,” Wang said. “This is a new measure, so we don’t have prior accumulation of knowledge. First we need to produce a normal reference atlas.

In resource-poor areas, this kind of detailed imagery could help make work and childbirth safer. To make the technology more accessible, Wang aims to use cheaper and more portable ultrasound imaging instead of expensive MRI scans, which are not widely available in many parts of the world.

Additionally, Wang’s team is producing disposable electrodes and wireless transmitters in close collaboration with University of Washington colleagues Chuan Wang, assistant professor of electrical and systems engineering; and Shantanu Chakrabartty, Professor of Electrical and Systems Engineering, with support from the Bill & Melinda Gates Foundation.

“We would like to develop a low-cost EMMI system that can be applicable in low- and moderate-resource environments,” says Yong Wang. “We are trying to make electrodes much cheaper by using printed disposable electrodes and a wireless transmitter.”

The March of Dimes, the National Institutes of Health’s National Institute of Child Health and Human Development, the Burroughs Wellcome Fund Preterm Birth Initiative and the Bill & Melinda Gates Foundation supported the work.

Source: Jacquelyn Kauffman for Washington University in St. Louis