Sunday, June 14, 2009

Monitoring Fetal Heartbeats

Tiny fluctuations in a fetus’s heartbeat can indicate distress, but currently there is no way to detect such subtle variations except during labor, when it may be too late to prevent serious or even fatal complications. Now a new system developed by MIT scientist Gari Clifford and colleagues was designed to make earlier monitoring of the fetal heartbeat possible. Additional researchers working on the project are from the Institut National Polytechnique de Grenoble, Sharif University, Tufts Medical Center, and E-TROLZ Inc.

Among other advantages, the system is expected to be less expensive and easier to use than current technologies. It could also cut the rate of Cesarean deliveries by helping clinicians rule out potential problems that might otherwise prompt the procedure. Finally, the device used today to monitor subtle changes in the fetal heartbeat during labor must be attached to the fetus itself, but the new product being developed would be noninvasive.

One of the methods used today to detect the fetal heartbeat is to use ultrasound but ultrasound is not sensitive enough to catch variations in the heartbeat rhythm that might indicate problems. Another method is to use electrocardiography to record the electrical activity of the heart to catch subtle changes in the heartbeat. However, until now there has been no reliable way to use the technique except by attaching an electrode to the baby’s scalp during labor.

Although it is possible to monitor the fetal ECG signal noninvasively through electrodes on the mother’s abdomen, the signal is weak compared to the maternal heartbeat and surrounding noise. It also has not been possible to separate the three signals without distorting characteristics of the fetal heartbeat key to identify potential clinical problems.

The new system separates the maternal ECG signal from the fetus’s and from background noise due to a complex algorithm derived from the fields of signal processing and source separations. Together these fields work to break any signal into its source components.

To use the system, which the team believes could be deployed during the second trimester of pregnancy and perhaps earlier, a woman would wear a wide belt around her abdomen fitted with several ECG electrodes. The prototype has 32, but that number will be lower in the final device. The data collected from the electrodes is then fed to a monitor and analyzed with the new algorithm which in turn, separates the different signals.

By monitoring the fetal ECG through the mother’s abdomen, you can get a multidimensional view of the fetal heart because its electrical activity is recorded from many different angles. The single probe used now to monitor the heartbeat during labor only gives data from one direction.

Principal colleagues on the signal processing work include Dr. Reza Sameni, Professor Christian Jutten of the Institut National Polytechnique de Grenoble, and Professor Mohammad B. Shamsollahi of Aharif University. The researchers have published papers in several journals.

Clifford’s key collaborator on the clinical work is Dr. Adam Wolfberg, an obstetrician and a fellow in maternal fetal medicine at Tufts Medical Center. To validate the algorithm and build the system, he turned to E-TROLZ. Dr Clifford expects the system to be commercially available in two to three years pending FDA approval.

The original development of the device was funded by the Center for Integration of Medicine and Innovative Technology. Recently several patent applications were licensed by MindChild Medical Inc.