New study suggests that the electromagnetic fields produced by the motors of an incubator may affect newborns’ heart rates. This effect is the more dangerous, as premature babies spend weeks or even months in incubators.

Incubators are usually used to help babies who are born prematurely in the period after birth. They generally isolate the baby from various stressors and maintain an appropriate temperature. This is the first research on the effect their electromagnetic fields can have on newborns.

“Neonatal incubators are designed to shield fragile babies from external foes and to preserve their temperature, and they are good for this. Yet we showed that most of them produce relevant electromagnetic fields, and this study is the first to show that this exposure has an influence on babies' autonomous nervous system,” said lead researcher Dr. Carlo Bellieni, of the University of Siena's Department of Pediatrics, Obstetrics, and Reproductive Medicine, according to the Atlanta Journal Constitution.

Dr. Bellieni and his colleagues looked at the changes of heart rates among 43 newborns none of whom were premature or critically ill. The experiment found that 27 of the infants underwent heart rate variability testing for 5-minute intervals while an incubator motor was on, off and on again. These babies experienced decreases in heart rate variability when the incubator was turned on.

The remaining 16 newborns were not exposed to an incubator motor, but were exposed to audio stimuli mimicking the sounds of a motor to see if noise might be a risk. These babies had no differences in heart rate variability.

“International recommendations and laws set levels to safeguard the health of workers exposed to [electromagnetic fields]: newborns should be worthy of similar protection, and follow-up programs of formerly premature babies should include the study of sympathetic activity development,” the researchers concluded.

Heart rate variability points to the normal alterations in heart rate that occur under resting conditions in healthy individuals. Decreased heart rate variability is a strong predictor of some cardiac abnormality in adults.

What the findings exactly mean for the babies’ health is not clear yet, so the researchers want to study further to see if there are any lasting effects.

“More research is needed to assess possible long-term consequences, since premature newborns may be exposed to these high [electromagnetic fields] for months,” they added.

The findings appear in the May 1 edition of the Fetal and Neonatal Edition of the Archives of Disease in Childhood.