Neonatal incubators especially designed to shield critically ill or premature babies from external foes and to keep the air surrounding the baby warm, may actually affect the heart rates of newborn babies by their electromagnetic field, results of a small Italian study report.

Though, the normal changes in heart rate were reduced when the machines were turned on, the Italian researchers found no hard evidence of any actual health damage caused by incubators.

However, whether these changes in cardiac rhythms have long-term effects on infants is still unknown, the radiations could have implications for premature infants who can spend several weeks or months in incubators, the researchers said.

For the study, the research team headed by Dr. Carlo Bellieni, of the University of Siena's Department of Pediatrics, Obstetrics and Reproductive Medicine, looked at the changes of heart rates among 43 newborns, who were critically ill or premature.

The heart rates of 27 babies were assessed over three five-minute periods during which the incubators motor was left on, then switched off and then turned on again.

To determine if the noise of the motor might be a factor, 16 of the infants were exposed to background noise, while the incubators motor was turned off.

The background noise did not affect heart rate, however, heart rate was significantly affected by the incubators, the researchers observed.

Also, when the incubator was turned on, the heart rate variability dropped significantly, the researchers noted. In adult patients with heart disease, a drop in heart rate variability is a strong predictor of poor outcomes, the researchers stated.

"Neonatal incubators are not electromagnetically neutral and this data deserves as much attention as the concerns about risks from cellular phones or high voltage lines on adults," Bellieni said.

The report is published in the May issue of the Archives of Disease in Childhood.