University of Florida physicians and a private engineering firm are developing what could be the first commercial monitoring system to noninvasively detect electrical activity in a baby’s heart, producing a foetal electrocardiogram, or EKG.
When perfected, the system might also distinguish false labour from early labour, and track the mother’s heart rate and the strength of her uterine contractions.
“There have been some preliminary studies by other groups that say foetal EKG is a more accurate predictor (than ultrasound) of how the baby’s doing during labour,” said Dr. Tammy Euliano, a UF associate professor of anesthesiology.
But currently, the only way to get that information is with what’s called a scalp electrode – a wire that is placed into the baby’s scalp during the final stages of labour.
The new system, however, uses sensors placed on the mother’s abdomen with an adhesive, so it could be used at any time during labour. And unlike the belts used for ultrasound monitors, the EKG sensors are unaffected by the mother’s movement or her body fat content.
But both systems have one thing in common: the problem of separating all the incoming signals, which include the baby’s heartbeat, the mother’s heartbeat, uterine contractions, muscle movement and noise.
And at present, that problem hasn’t been resolved sufficiently for noninvasive EKG monitors to reach the market, added Neil Euliano, president of Convergent Engineering, the Gainesville, FL-based biomedical engineering company involved in the project.
The system developed by the researchers in Florida includes an amplifier that magnifies foetal EKG signals without affecting the much stronger maternal signals, as well as a program to separate data from multiple sources. Once separated, other programs calculate and label the foetal and maternal heartbeats and assign a “trust factor” to indicate the information’s reliability.
In the next few years, the UF/Convergent research team plans to refine its system by monitoring hundreds of patients with ultrasound monitors and the EKG system. Not only will they compare results from the two, they also will look for features in the foetal EKG readings that could indicate foetal well-being, labour characteristics and abnormal foetal heart rhythms.
Ultimately, foetal heart rate may be one of the less important pieces of data the EKG system delivers. Although continuous foetal heart rate monitoring is a standard practice for birth care, it’s used primarily because it’s the only data doctors can obtain.
And so the researchers are also interested in finding features in the pattern of electrical activity of the EKG that would correlate strongly to foetal well-being and give doctors better information than ultrasound provides.
If further testing and refinement shows the new system is reliable and applicable to clinical situations, a commercial version could be marketed in three to four years.