To clear these hurdles, Nottingham researchers worked to design a low-noise apparatus, consisting of a digital-processing body, leads, and electrodes. They then found that using more than two electrodes increased their chances of detecting a fetal, as well as a maternal, heartbeat. The fetus's heart rate emerged after scientists applied a heart-rate extraction algorithm to the data, in effect subtracting the mother's large heartbeat from the overall output. They could then identify the smaller peaks and amplitudes, indicating the fetus's heartbeat.

Hayes-Gill and his colleagues tested an initial device on 400 pregnant women. They are currently testing the most recent prototype, which they hope to launch commercially, on 44 women, all within 28 to 32 weeks of pregnancy. During the experiments, the women are asked to wear the monitors, with electrodes taped to their abdomens, for 16 to 20 hours. During the day, the women are instructed to go about their normal activities, barring bathing and showering. The device itself has no display but is Bluetooth enabled to send data to a PC, where scientists can analyze the data with heart-rate extraction software. Martin says that so far, scientists have been able to accurately identify fetal heartbeats 90 percent of the time.

"A mother can walk around, sleep, do what she wants," he says. "We can monitor mothers at home very easily because the device doesn't require supervision, and there's no skill required to stick the electrodes on."

Eventually, Martin envisions selling the user-friendly, handheld monitor to hospitals and private practices, where doctors can prescribe them to high-risk mothers and analyze the incoming data for any irregularities. He anticipates that the device will be on the market in Britain by September and in the United States by the summer of 2008.

"This technology could be a much-needed improvement to existing methods of fetal monitoring," says Tammy Euliano, associate professor of anesthesiology, obstetrics, and gynecology at the University of Florida at Gainesville. "However, reliability will be vital in that inaccurate recordings could lead to a false sense of security regarding fetal well-being, or, more likely, [to] undue concern, repeated calls to the OB, and/or trips to the hospital."